Abstract: Polyamide fibres are colored with dyestuffs of the formula: ##STR1## wherein A represents the residue of a carbocyclic diazotisable amine, R represents an alkyl group, U represents a linear or branched alkylene group of 1 to 5 carbon atoms, V represents an arylene group, and A, B, R and V are unsubstituted or substituted with non-water-solubilizing substituents, and a process for their preparation which comprises diazotising an amine of the formula:A -- NH.sub.2and coupling the diazo derivative thus obtained with a coupling component of the formula: ##STR2## wherein A, B, R, U and V have the same significance as above. The polyamide fibres exhibit excellent tinctorial yield, very remarkable brilliance, good fastness to washing and to light and good covering of bars.

Abstract: Process for the coloration of cellulosic textile fibers which comprises applying thereto, in the presence of thiourea, a dyestuff containing in its molecule at least one sulphinic group, and fixing the dyetuff by means of a treatment at a temperature ranging from 100.degree. C to 200.degree. C.