High molecular weight organic material is effectively colored by the incorporation therein of a copper or nickel complex of the ligand compound of formula I ##STR1## wherein A is an isocyclic or heterocyclic aromatic moiety, R is H, halogen, lower alkyl or alkoxy, R.sub.1 is H, lower alkyl, phenyl or substituted phenyl, and B is H, lower alkyl, ureido or substituted ureido, guanidino, anilino, benzamido or a heterocyclic aromatic moiety.