2 - (Stilbyl - 411) - (naphtho - 11:21:4:5)-1:2:3-triazole brightening agents of the formula: <FORM:0781821/IV (b)/1> in which Z represents an acid salt-forming group and n is an integer of from 1 to 4 and which contain no auxochromes or chromophores but wherein the aromatic rings can be further substituted by admissible substituents (except in the stilbene radical by acylamino groups, triazinylamino groups and azol rings), provided that a sulphonic acid group does not occupy the X1 position if the benzene ring A contains no other substituent and with the further condition that at least one substituent, preferably an electrophilic substituent, is present in the X1, X2 and X3 positions, and salts (e.g. alkali metal salts) of such compounds, are applied by means of rinsing liquors, soap dispersions or chemical bleaching liquors containing hypochlorite to fibres consisting of cellulose, cellulose acetate, cotton, linen, superpolyamides (e.g. nylon and perlon), superpolyurethanes, polyvinyl chloride, polyvinylidene chloride and copolymers of the latter two materials. Specified admissible substituents are hydrocarbon radicals, halogens and ether, cyano, carboxyl, carboxylic amide, carboxylic anilide, sulphonic acid, sulphonamide, N-substituted sulphonamide, sulphonic ester and sulphone groups. In examples white cotton poplin is treated in a bath with a solution of Glauber's salt containing brightening agent; white washing comprising sheets and pillow cases is treated with a washing liquor containing grain soap, sodium bicarbonate and brightening agent; and nylon material is treated with a sodium chloride solution containing brightening agent. Azo dyes.-4-Aminostilbene compounds having, in an ortho-position to the ethylene linkage of the benzene nucleus containing the amino group, hydrogen, a substituent other than a sulphonic acid group, or a sulphonic group accompanied by at least a further substituent in said nucleus, are diazotized and coupled with aminonaphthalene compounds coupling in the neighbouring position to the amino group to form the corresponding ortho-aminoazo dyestuffs. Specified 4-aminostilbene compounds are 2-cyano-4-aminostilbene, 2 - carboxy - 4 - aminostilbene, 2 - sulphonic acid phenyl, ortho - cresol and para - cresyl ester - 4 - aminostilbenes, 2-chloro - 4 - aminostilbene, 2 - methoxy - 4-aminostilbene, 2 - methylsulphonyl, 2 - ethylsulphonyl, 2 - vinylsulphonyl, 2 - butylsulphonyl, 21 - phenylsulphonyl, 2 - para - toluylsulphonyl, 2 - (21:41 - xylysulphonyl) and 2(31:41 - xylysulphonyl) - 4 - aminostilbenes, 4-aminostilbene - 2 - sulphonic acid dimethyl and diethyl amides, 2 - methyl - 4 - aminostilbene-21 - and 41 - sulphonic acids, 2 - fluoro - 4-aminostilbene - 21 - and 41 - sulphonic acids, 2-chloro - 4 - aminostilbene - 21 - and 41 - sulphonic acids, 2 - methoxy - 4 - aminostilbene - 21 - and 41 - sulphonic acids, 2 - ethoxy - 4 - aminostilbene - 21 - and 41 - sulphonic acids, 4 - aminostilbene - 21 - sulphonic acid, 4 - amino - 21-chlorostilbene - 51 - sulphonic acid, 4 - aminostilbene - 41 - sulphonic acid, 4 - amino - 21-and (41 - methylsulphonyl - stilbenes, 4 - amino-21 - and 41 - ethylsulphonyl - stilbenes, 4-aminostilbene - 21 - sulphonic acid cyclohexylamide, 4 - aminostilbene - 21 - sulphonic acid dimethyl and diethyl amides, 4-aminostilbene-41 - sulphonic acid dimethyl and diethyl amides, 6 - methyl - 4 - aminostilbene - 2 - sulphonic acid, 6 - chloro - 4 - aminostilbene - 2-sulphonic acid, 4 - aminostilbene - 2 - sulphonic acid acetimide, 4 - aminostilbene - 2 - sulphonic acid benzoylimide, 4 - aminostilbene - 2 - sulphonic acid methylsulphimide, 4-aminostilbene-2 - sulphonic acid benzene sulphimide, 4-aminostilbene - 2 - sulphonic acid para - chlorobenzene sulphimide and 4 - aminostilbene - 2-sulphonic acid - para - methylbenzene sulphimide. Specified aminonaphthalene compounds are 2 - naphthylamine, 1 - naphthylamine, 2-aminonaphthalene - 6 - sulphonic acid, 2-aminonaphthalene - 5:7 - disulphonic acid and 2-aminonaphthalene-5-sulphonic acid.ALSO:2 - (Stilbyl - 411) - (naphtho - 11:21:4:5)-1:2:3-triazole brightening agents of the formula: <FORM:0781821/III/1> in which Z represents an acid salt-forming group and n is an integer of from 1 to 4, and which contain no auxochromes or chromophores but wherein the aromatic rings can be further substituted by admissible substituents (except in the stilbene radical by acylamino groups, triazinylamino groups and azol rings), provided that a sulphonic acid group does not occupy the X1 position if the benzene ring A contains no other substituent and with the further condition that at least one substituent, preferably an electrophilic substituent, is present in the X1, X2 and X3 positions, and salts (e.g. alkali metal salts) of such compounds, are added to soaps, synthetic washing agents and to organic solvents used for the chemical cleaning of textile fibres. Specified admissible substituents are hydrocarbon radicals, halogens and ether, cyano, carboxyl, carboxylic amide, carboxylic anilide, sulphonic acid, sulphonamide, N-substituted sulphonamide, sulphonic ester and sulphone groups. In an example 2 (211-cyanostilbyl-411)-(naphtho - 11:21:4:5) - 1:2:3 - triazole - 61-sulphonic acid or 51:7-disulphonic acid is added to a washing liquor containing grain soap and sodium carbonate.ALSO:The invention comprises 2-(stilbyl-411)-(naphtho - 11 : 21 : 4 : 5) - 1 : 2 : 3 - triazoles of the formula: <FORM:0781821/IV (a)/1> which contain no auxochromes or chromophores, and wherein the aromatic rings can be further substituted by admissible substituents except in the stilbene radical by acylamino groups, triazinylamino groups and azol rings, providing a sulphonic acid group does not occupy the X position if the benzene ring A contains no other substituent and with the condition that at least one substituent, preferably an electrophilic substituent, is present in the X1, X2 and X3 positions, Z represents an acid salt-forming group and n is an integer of from 1 to 4, and the salts of such compounds. Specified admissible substituents are hydrocarbon radicals (e.g. methyl, isopropyl, tert.butyl, amyl and phenyl groups); ether groups (e.g. methoxy, ethoxy, propoxy, butoxy, benzyloxy and phenoxy groups); halogens (e.g. chlorine, bromine and fluorine), cyano, carboxyl, carboxylic amide carboxylic anilide, sulphonic acid and sulphonic acid amide groups; sulphonic ester groups (e.g. sulphonic acid phenyl, ortho-cresyl, meta-cresyl, para-cresyl, orthochlorophenyl and para - chlorophenyl ester groups); N-substituted sulphonamide groups (e.g. N - methyl -, N - ethyl -, N - oxyethyl -, N - dimethyl -, N - diethyl -, N - phenyl -, N-methyl - N - phenyl -, N - ethyl - N - phenyl-, N - methylsulphonyl -, N - acetyl - and N-benzoyl-sulphonamide groups; N - piperidino-sulphonyl and N - morpholinosulphonyl groups); and sulphone groups (e.g. methyl, ethyl, vinyl, n-butyl, para-tolyl, 2 : 4-xylyl and 3 : 4 - xylyl - sulphonyl groups). Specified acid salt-forming groups are carboxyl, alkylsulphonylsulphonic acid, arylsulphonylsulphonic acid, acylsulphonamide and sulphonic acid groups. Alkali metals are specified as salt-forming anions. The compounds are prepared by coupling diazotized 4-aminostilbene compounds having in an ortho-position to the ethylene linkage of the benzene nucleus containing the amino group, hydrogen, a substituent other than a sulphonic acid group, or a sulphonic acid group accompanied by at least a further substituent in said nucleus, with aminonaphthalene compounds coupling in the neighbouring position to the amino group to form the corresponding ortho-aminoazo dyestuff, and oxidizing this to form the corresponding 1 : 2 : 3-triazole compound, the components being so chosen that the products are of the above general formula and either contain no inadmissible substituents or contain nitro, acylamino or amino groups, the former two groups being subsequently reduced and saponified respectively to amino groups and the latter being diazotized and the diazo group being replaced by hydrogen by boiling in alcohol, or by admissible substituents according to Sandmeyer's method. The products are purified by treatment with reducing agents such as alkali hydrosulphite or if necessary are de-coppered with alkali sulphides and recrystallized from their solutions in water or aqueous organic solvents. The examples describe the preparation of 2 - (211 - cyanostilbyl - 411) - (naphtho-11 : 21 : 4 : 5) - 1 : 2 : 3 - triazole - 61 - sulphonic acid, 2 - (211 - cyanostilbyl - 411) - (naphtho-11 : 21 : 4 : 5) - 1 : 2 : 3 - triazole - 51 : 71 - disulphonic acid, 2 - (stilbyl - 411) - (naphtho-11 : 21 : 4 : 5) - 1 : 2 : 3 - triazole - 211 - carboxylic acid, 2 - (stilbyl - 411) - (naphtho - 11 : 21 : 4 : 5) - 1 : 2 : 3 - triazole - 211 - carboxylic acid - 61 - sulphonic acid, 2 - (stilbyl - 411) - (naphtho - 11 : 21 : 4 : 5) - 1 : 2 : 3 - triazole - 211 - sulphonic acid phenyl ester - 51 : 71 - disulphonic acid, 2 - (stilbyl - 411) - (naphtho - 11 : 21 : 4 : 5 - 1 : 2 : 3 - triazole - 211 - methylsulphone - 61 - sulphonic acid, 2 - (stilbyl - 411) - (naphtho-11 : 21 : 4 : 5) - 1 : 2 : 3 - triazole - 211 - methylsulphone - 51 - sulphonic acid, 2 - (stilbyl - 411) - (naphtho - 11 : 21 : 4 : 5) - 1 : 2 : 3 - triazole - 211 - (1 : 3 - dimethylphenylsulphone) - 61 - sulphonic acid, 2 - (stilbyl - 411) - (naphtho - 11 : 21 : 4 : 5) - 1 : 2 : 3 - triazole - 211 - (1 : 3 - dimethylphenylsulphone) - 51 : 71 - disulphonic acid, 2 - (stilbyl-411) - (naphtho - 11 : 21 : 4 : 5) - 1 : 2 : 3 - triazole-211 - sulphonic acid dimethylamide - 61 - sulphonic acid, 2 - (stilbyl - 411) - (naphtho-11 : 21 : 4 : 5) - 1 : 2 : 3 - triazole - 211 - sulphonic acid dimethylamide - 51 - sulphonic acid, 2 - (211 - chlorostilbyl - 411) - (naphtho - 11 : 21 : 4 : 5) - 1 : 2 : 3 - triazole - 4111 - sulphonic acid, 2 - (2