This work reports the crystal structure of [(Z)-2-((E)-1-{6-[1-({[amino(sulfanidyl-κS)methylidene]amino}imino-κN)ethyl]pyridin-2-yl-κN}ethylidene)-1-cyanohydrazinido-κN¹]copper(II), [Cu(C₁₁H₁₁N₇S)], the first description of a copper(II) complex of 2,6-diacetylpyridine bis(thiosemicarbazone) showing partial conversion of a thioamide group to a nitrile group. The asymmetric ligand coordinates to the metal centre in anN,N′,N′′,S-tetradentate mannerviathe pyridine N atom, an imine N atom, the hydrazinide N atom and the sulfanidyl S atom, displaying a square-planar geometry. Ligand coordination results in two five-membered chelate rings and one six-membered chelate ring, and in crystal packing based on N—H...N hydrogen bonds of the cyanohydrazinide and hydrazinecarbothioamidate arms of the ligand. The correlation between the partial conversion upon metal complexation, H₂S release and possible effects on the activity of bis(thiosemicarbazone)s as drug prototypes for Alzheimer's disease is also discussed.