Azo dyestuffs are manufactured by coupling a compound of the general formula <FORM:0588165/IV/1> wherein X represents an alkyl, aralkyl or aryl group or an amino group, which may contain substituents, with a diazo compound from an amine containing, in o-position to the amino group, an atomic grouping capable of participating in the formation of metal complexes in the resulting dyestuff, e.g. sulphonated or unsulphonated o-aminophenols, o-aminonaphthols and o-aminocarboxylic acids. The products dye animal fibres yellow to red and brown shades, which change to brown or deeper shades when after-chromed. Many of the products may be used with the addition of a chromium mordant in the single-bath process. Complex metal (e.g. chromium) compounds of the dyestuffs may also be prepared in substance, and, if they contain groups imparting solubility, may be used as acid dyestuffs. Examples (1) to (4) and a table describe the preparation of dyestuffs from 2 : 4-diaminobenzene-1-methyl-or -ethyl-sulphone, -1-sulphonamide or -1-sulphodiethylamide and the diazo compounds from 4 : 6-dinitro-, 4- or 5-nitro-, 4-chloro- or 4 - chloro - 5 - nitro - 2 - aminophenol, 2 - amino - phenol-4-sulphonic acid or -4-sulphonamide, 4-chloro- or 4-nitro-2-aminophenol-6-sulphonic acid, 6 - nitro - 2 - aminophenol - 4 - sulphonic acid, 1-aminobenzene-2-carboxylic acid or its 4- or 5-sulphonic acid, or a chlorinated or brominated anthranilic acid. In further examples: (5) wool is dyed brown with the dyestuff 4 : 6-dinitro - 2 - aminophenol --> 2 : 4 - diamino - benzene - 1 - sulphonamide from a bath containing aminonium sulphate, sodium chromate, Glauber salt and, in the latter stages, acetic acid; (6) wool is dyed with the dyestuff 4 : 6-dinitro - 2 - aminophenol --> 2 : 4 - diamino - benzene-1-methyl-sulphone in a bath containing acetic acid, Glauber salt and, in the latter stages, sulphuric acid, and is after-treated in the same bath with potassium bichromate, yielding a brown shade. Additional components specified are: diazo components: 2-aminophenol and its 4 : 6-dichloro-, 3 : 4 : 5 : 6-tetrachloro-, 4-methyl-, 4-chloro - 6 - nitro- and 4-nitro-6-chloro-derivatives, 6-chloro-2-aminophenol - 4 - sulphonic acid, 4 - methyl - 2 - aminophenol-6-sulphonic acid, 1-amino-2-naphthol-4-sulphonic acid and its nitrated and halogenated derivatives, 2 - amino - 1 - naphthol - 4 : 8 - disulphonic acid, 2-aminonaphthalene-3-carboxylic acid, and the 4-chloro-, 4-nitro-, 4-acetylamino-and 4 : 6 - dibromo - derivatives of 1 - aminobenzene - 2 - carboxylic acid; coupling components: 2 : 4 - diaminobenzene - 1 - benzyl- and -phenyl-sulphone and -1-sulphanilide, and derivatives containing a group imparting solubility in water, e.g. a sulphonic acid group, in an aryl nucleus other than that containing the two amino groups. 2 : 4 - Diaminobenzene - 1 - sulphones and -sulphonamides, of the general formula given above, are obtainable by subjecting 2 : 4-nitrobenzene-1-sulphochloride to reduction of the sulphochloride group to a sulphinic acid group followed by alkylation or aralkylation, to reaction with an aromatic hydrocarbon by the Friedel-Crafts method, or to reaction with ammonia or an appropriate amine, e.g. diethylamine, and in each case finally reducing the two nitro groups to amino groups; or, in the case of the 1-alkyl-sulphones, by treating 2 : 4-dinitrochlorobenzene with sodium disulphide, reducing the resulting 2 : 4 : 21 : 41-tetranitrodiphenyl disulphide with sodium sulphide in alcohol, converting the product into a thio-ether by treatment with an alkylating agent, e.g. dimethyl or diethyl sulphate, oxidizing the thio-ether group to the sulphone group with hydrogen peroxide in glacial acetic acid, and reducing the nitro groups by means of iron; or, in the case of the 1-methyl-sulphone, by condensing 2 : 4-dinitrothiophenol (prepared as above) with chloracetic acid, oxidizing the resulting 2 : 4-dinitrothioglycollic acid to the corresponding sulphone with hydrogen peroxide, splitting of the carboxyl group and reducing the nitro groups. 2 : 4 - Dinitrobenzene - 1 - sulphochloride is obtainable by chlorinating 2 : 4 : 21 : 41-tetranitrodiphenyl disulphide in suspension in acetic acid.