Novel 4-(v-triazolyl)-styryl compounds of the formula ##STR1## wherein n is 0, 1 or 2, R represents a hydrogen atom or an unsubstituted or substituted alkyl, alkenyl, aralkyl, alkanoyl or aroyl group and Q represents an unsubstituted or substituted 5-membered heterocyclic ring or, if n is 1 or 2, also represents hydrogen, the rings A, B and C being optionally substituted with further non-chromophoric substituents, processes for their preparation as well as a process for optically brightening organic materials on using said compounds are disclosed.