Mixtures of different oligomer compounds of formula (1) are suitable for use as direct dyes for dyeing and printing a wide range of materials, especially cellulose fibers, to give dyeings and prints of good all-round fastness properties: ##STR1## wherein R.sub.1 is hydrogen or unsubstituted or substituted alkyl, cycloalkyl, aryl or aralkyl, R independently has the meaning of R.sub.1 or is an unsubstituted or substituted heteroaryl radical or a radical of formula ##STR2## wherein R.sub.4 is unsubstituted or substituted alkyl, cycloalkyl, aryl, aralkyl or heteroaryl, A is an unsubstituted or substituted alkylene, cycloalkylene, arylene or aralkylene radical, X is --O--, --S-- or --N(R.sub.5)--, wherein R.sub.5 is hydrogen or unsubstituted or substituted alkyl, cycloalkyl, aryl or aralkyl, or wherein the group ##STR3## is an unsubstituted or substituted heterocyclic radical, Y is C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, halogen, sulfo, carboxy, carbamoyl, N-mono- or N,N-di-C.sub.1 -C.sub.4 alkylcarbamoyl, N-phenyl- or N,N-diphenylcarbamoyl, sulfamoyl, N-mono- or N,N-di-C.sub.1 -C.sub.4 alkylsulfamoyl or N-phenyl- or N,N-diphenylsulfamoyl, Z is hydroxy or unsubstituted or substituted alkyl, aryl or aralkyl, R.sub.2 and R.sub.3 are each independently of the other hydrogen, halogen, cyano, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, unsubstituted or substituted phenyl, benzyl, benzoylamino or phenoxy, sulfo, carboxy, carbamoyl, phenylcarbamoyl or C.sub.2 -C.sub.5 alkanoylamino, B is a bivalent organic linking group, m is an integer from 1 to 6 and n and p are each independently of the other 0 or 1, with the proviso that the different compounds of formula (1) of the mixture of oligomers differ solely in the value of m.