Azo dyes, forming on the material.--Fast dyeings are obtained on mixtures of different fibres by treating such mixtures in an p acid bath with acid-soluble coupling components, free from sulphonic acid groups and having affinity for the fibres, and causing diazotized cyclic amino compounds to couple with such components upon the fibres. Specified mixtures dyed are mixtures of two or more of the following types of fibre, viz.: wool, silk, cotton, linen, hemp, regenerated cellulose. synthetic resin or cellulose ester or ether. Specified coupling components are acid-soluble aza compounds of high molecular weight containing hydroxy or amino groups and acid-soluble amides of o-hydroxycarboxylic acids or ketocarboxylic acids containing aza groups (cf. Specifications 451,932, 461,425, and 463,456). The following examples are specified: (1) a mixed fabric of wool and viscose artificial silk or of wool and cotton is dyed a uniform scarlet, fast to washing and rubbing, by impregnating it for \ba1/2\be hour with an aqueous solution at 50 DEG C. containing 9-methylamino-4-azaphenanthrene and formic acid and developing by treatment for \ba1/2\be hour with an aqueous solution at 25 DEG C. of diazotized 4-chloro-3-aminobenzotrifluoride; if the coupling component is replaced by 9-dimethylamino-4-azaphenanthrene and the diazo component by 4-nitraniline, the dyeing is violet; (2) a mixed fabric of wool and cotton or wool and viscose artificial silk or wool and regenerated cellulose staple fibre is dyed yellow, fast to washing, rubbing, light and weather, by impregnating it for \ba1/2\be hour in an aqueous solution at 50 DEG C. containing 9-acetoacetylamino-4-azaphenanthrene and sulphuric acid, developing by treatment for \ba1/2\be hour with an aqueous solution at 20 DEG C. of diazotized 4-chloro-2-aminotoluene, rinsing and treating for \ba1/2\be hour with a boiling aqueous solution of a non-alkaline washing agent and sodium hydrosulphite; by varying the temperatures of the baths or the amount of sulphuric acid used various strengths of dyeings may be obtained on the wool as compared with the other fibres. (3) a mixed fabric of cotton and wool or viscose artificial silk is dyed golden yellow, fast to washing, rubbing and light, by impregnating it for \ba1/2\be hour in an aqueous solution at 50 DEG C. containing aminohydroxy - 4 - azaphenanthrene and formic acid and developing by treatment for \ba1/2\be hour with an aqueous solution at 30 DEG C. of diazotized 1-amino-3-methyl-4-cyano-6-chlorobenzene; the diazo components in examples (1) to (3) may be replaced, to vary the shades of the dyeings, by 2 : 5-dichloraniline, 2-methoxyaniline - 5 - benzyl- or 5 - ethyl - sulphone, 2-nitraniline, 5-chloro- or 5 - nitro - 2 - aminotoluene, 3-chloraniline, 2-aminodiphenylsulphone, 3-nitro-4-aminotoluene, 1-trifluoromethyl - 3 - aminophenyl - 4 - ethylsulphone, 1-amino - 2 - trifluoromethyl - 4 - chlorobenzene, 4-amino-3-or 4<1>-methoxydiphenylamine, 4-aminodiphenylamine, 1 - methoxy - 2 - amino - 5 - nitrobenzene, 1 - methoxy - 4 - amino - 3 - nitrobenzene, 2 : 5-dimethoxy or diethoxy - 4 - benzoylaminoaniline, dianisidine or 3-amino-4-methoxy-6-benzoylaminotoluene; (4) a mixed fabric of wool and regenerated cellulose staple fibre is dyed a fast strong red by impregnating it for \ba1/2\be hour with an aqueous solution at 50 DEG C. containing 2<1> : 3<1>-hydroxynaphthoyl-2-aminopyridine and sulphuric acid, developing by treatment for \ba1/2\be hour with an aqueous solution at 40--50 DEG C. of diazotized 4 : 4<1>-dichloro-2-aminodiphenyl ether, rinsing and treating for \ba1/2\be hour at the boil with a non-alkaline washing agent; (5) a mixed fabric of wool and regenerated cellulose staple fibre is dyed uniformly an intense reddish yellow by impregnating it for \ba1/2\be hour with an aqueous solution at 50 DEG C. containing 1 - (8<1>-quinolyl)-3-methyl-5-pyrazolone and acetic acid, developing by treatment for \ba1/2\be hour with an aqueous solution at 20--30 DEG C. of diazotized 4 - chloro - 2 - aminotoluene and further treating as in (4). Aminohydroxy-4-azaphenanthrene is obtained by treating 1 : 3-dihydroxy-4-azaphenanthrene with aqueous ammonia under pressure. 1 - Amino - 3 - methyl - 4 - cyano - 6 - chlorobenzene is obtained by chlorinating 2-cyanotoluene, nitrating the product and reducing the nitro group. 2-Methoxyaniline-5-benzyl- and 5-ethyl-sulphones are obtained by oxidizing the reaction products of 1-mercapto-3-amino-4-methoxybenzene with benzyl and ethyl chlorides respectively. 2<1> : 3<1>-Hydroxynaphthoyl - 2 - aminopyridine is obtained by reacting 2-aminopyridine with 2-acetoxy-3-naphthoyl chloride and splitting of the acetyl group by gentle heating with sodium hydroxide solution. 1-(8<1>-Quinolyl) - 3 - methyl - 5 - pyrazolone is obtained by reacting 8-hydrazinoquinoline with acetoacetic ester. Reference has been directed by the Comptroller to Specification 462,715.