Abstract: A dyestuff of formula: ##STR1## wherein: the groups X.sub.1 and X.sub.2 are independently hydrogen, halogen, alkyl, aryl, alkoxy, cyano, optionally substituted amino or carboxylic acid ester groups; (R).sub.n represents n substituents R each of which is independently halogen, lower alkyl, lower alkoxy or --COOH and n is 0 or 1; R.sub.1 is hydrogen, or optionally substituted lower alkyl; Y is an optionally substituted aliphatic or optionally substituted araliphatic group; R.sub.2 is hydrogen, optionally substituted lower alkyl, optionally substituted aryl or optionally substituted aralkyl; R.sub.3 is hydrogen or an optionally substituted alkyl or aralkyl group; A.sup.- is an anion; a is 0 or 1; and Z is hydrogen, optionally substituted lower alkyl, optionally substituted aryl or optionally substituted aralkyl.The dyes are useful for the coloration of materials such as textiles, leather, inks and lacquers.