Abstract: A compound having the formula: ##STR1## wherein X represents a --SO.sub.3 H or PO.sub.3 H.sub.2Y represents hydrogen, chlorine, alkyl, alkoxy or nitro,Z represents hydrogen,B represents a p-phenylene or 1,4-naphthylene unsubstituted or substituted by one or two alkyl or alkoxy groups,R represents hydrogen, alkyl or alkoxy,R.sub.1 represents hydrogen, chlorine, alkyl, alkoxy or acetylamino,R.sub.

Abstract: Dyestuffs of the formula: ##STR1## in which R.sub.2 and R.sub.4 which are the same or different each represent a hydrogen atom or an alkyl, hydroxyalkyl or cyanethyl group, one of the substituents R.sub.1 and R.sub.3 represents the 2,2,2-trifluoroethyl group and the other substituent represents an alkyl group or the 2,2,2-trifluoroethyl group, the ring A is unsubstituted by or substituted by one or 2 chlorine atoms or an alkoxy or alkyl group, the rings B.sub.1 and B.sub.2 are each unsubstituted or substituted by at least one alkyl or alkoxy group and X represents a colorless monovalent anion; process for the preparation of such dyestuffs; process for the coloration with such dyestuffs based on a polymer or copolymer of acrylic nitrile or on polyamides or polyesters which have been modified by anionic groups; and fibres based on a polymer or copolymer of acrylic nitrile or on polyamides or polyesters which have been modified by anionic groups colored by means of such dyestuffs.