Diazoamino derivatives are prepared by condensing a diazo compound, in non-acid medium, with a compound of formula: <FORM:0753591/IV(a)/1> or a salt thereof, in which X is a substituted or unsubstituted alkyl group. Specified substituents in X are -OH, -OCH3, -OC2H5, -COOH, -SO3H, -OSO3H, -OPO3H2, -OPO2H2, -COO alkyl and -CON<. Specified amines from which the diazo compounds are derived are aniline, toluidines, xylidines, cresidines, anisidines, halogen substituted anisidines, monochloroanilines, nitroanilines, nitrotoluidines, nitroanisidines, nitrocresidines, monoacylated paradiamines which may be substituted by halogen atoms or alkyl or alkoxy groups, aromatic monoamines containing sulphamido, sulphone, or trifluoromethyl groups, aminobenzothiazoles, aminoindazoles and aminoazo dyestuffs. The diazoamino derivatives can be mixed with coupling components and used to prepare azo dyes on textile fibres (see Group IV (c)). In examples: (1) 4 : 41-di-N-methylamino - diphenylmethane - 3 : 31 - dicarboxylic acid is dissolved in sodium carbonate solution sodium hyposulphite is added, and a solution of the diazo compound from 1-amino-4-benzoylamino - 2 : 5 - dimethoxy - or - diethoxybenzene is slowly added thereto, the mixture is made alkaline with sodium hydroxide, and the diazoamino derivative is precipitated by the addition of a mixture of sodium hydroxide and sodium chloride; (2) diazotized 5-chloro-2-amino-1-methylbenzene is reacted with 4 : 41-di - N - methylamino - diphenylmethane-3 : 31 - dicarboxylic acid; (3) diazotized 1-amino - 5 - diethylsulphonamido - 2 - methoxybenzene is reacted with 4 : 41-di-N-hydroxyethylamino - diphenylmethane - 3 : 3 - dicarboxylic acid; (4) and (5) diazotized 4-chloro-2-amino-1- methylbenzene or 1-amino-5-diethyl- or - dimethylsulphamido - 2 - methylbenzene is reacted with 4 : 41-di-N-carboxymethylaminodiphenylmethane-3 : 31-dicarboxylic acid. 4 : 41 - Di - N - methylamino - or hydroxyethylamino - or - carboxymethylaminodiphenylmethane - 3 : 31 - dicarboxylic acids. These compounds are prepared by reacting the corresponding N-substituted anthranilic acids with formaldehyde in the presence of hydrochloric acid.ALSO:Diazoamino derivatives, prepared by condensing a diazo compound with a compound of formula <FORM:0753591/IV(c)/1> in which X is a substituted or unsubstituted alkyl group, are mixed with coupling components and developed to give azo dyestuffs on textile fibres of natural or regenerated cellulose. In examples (6) the diazoamino compound obtained by reacting diazotized 5 - chloro - 2 - amino - 1 - methyl-benzene with 4:41-di-N-methylamino - diphenylmethane-3:31-dicarboxylic acid is mixed with the sodium salt of the o-toluidide of b -hydroxynaphthoic acid and sodium sulphate, the mixture so obtained is pasted with water. denatured alcohol. caustic soda, sodium chloride and starch-tragacanth thickener, the paste printed on a cotton fabric and steamed with neutral steam to give yellowsih-red prints (the o-phenetidide of b -hydroxy-naphthoic acid and diacetoacetyl tolidine may also be used as coupling components in the above process and give scarlet and yellow prints respectively) (7) the diazoamino derivative obtained by reacting diazotized 1-amino-5 - diethylsulphamido - 2 - methoxy-benzene with 4:41-di-N-hydroxyethylaminodiphenylmethane-3 : 31-dicarboxylic acid is mixed with the 51-chloro-21 : 41-dimethoxyanilide of b -hydroxy-naphthoic acid, the mixture pasted with water, caustic soda, "Solutene Cl," sodium chlorate and starch-tragacanth thickener, the paste printed on a cotton fabric and steamed in neutral steam to give bluish-red prints; (8) the diazoamino derivative prepared by reacting diazotized 1-amino-5-dimethylsulphamido-2-methyl-benzene with 4 : 41-di-N-carboxymethylamino - diphenylmethane - 3 : 31 - dicarboxylic acid is mixed with the 41-chloro-21 : 51-dimethoxy-anilide of b -hydroxynaphthoic acid and treated as in (7) to give yellowish red prints; (9) the diazoamino derivative prepared by reacting diazotized 1-amino - 4 - benzoylamino - 2:5 - dimethoxy-benzene with 4:41-di-N-methylaminodiphenylmethane-3:31 -dicarboxylic acid is mixed with the sodium salt of the anilide of b -hydroxynaphthoic acid and the mixture treated as in (7) to give blue prints.