Abstract: Heavy-metal-containing bisformazan dyestuffs of the formula ##STR1## WHEREIN A.sub.1, A.sub.2, B.sub.1 and B.sub.2 are the same or different and each represents an unsubstituted or substituted o-phenylene radical or an o-naphthylene radical,R.sub.1 and R.sub.2 are the same or different and each represent a monovalent organic radical,Me.sub.1 and Me.sub.2 each represent nickel or copper,X.sub.1 and X.sub.2 are the same or different and each represents a metal-binding substituent connected to A.sub.1, B.sub.1, A.sub.2 or B.sub.2 in a position ortho to that to which the nitrogen is linked,Y represents the radical of a dibasic carboxylic acid or a radical which is derived from an, at least, bifunctional heterocyclic compound,Z represents a salt-forming water-solubilizing group, dissociating acid in water, selected from --SO.sub.3.sup..crclbar. M.sym. and --COO.sup..crclbar. M.sup..sym.wherein M.sup..sym.

Abstract: The present invention provides heavy metal complexes of azo dyes of the formula ##STR1## wherein each of A and A' represents a coupling component of the phenylenediamine, naphthol, naphthylamine, pyrazolone, aminopyrazole, acylacetamide, pyridone, 2,4,6-triaminopyridine or barbituric acid series, which is bound in ortho-position to a hydroxy, amino or enolisable keto group to the azo group, while A and A' carry at least one sulpho group and contain no other ionogenic substituents.