Highly suitable for dyeing polyester fibre materials are mixtures of dyes of the formulae <IMAGE> where R1-R8 are each C1-C4-alkyl and R1-R6 may in addition also be -(A-O)nC1-C4-alkyl, where A is a C2-C4-alkylene radical and n is from 1 to 4. The dyeings obtained are notable for the absence of catalytic fading.
