Abstract Four dinucleating bis (thiosemicarbazone) ligands and their zinc complexes have been synthesized and characterized by multinuclear NMR (1 H and 13 C), IR, UV–Vis, ESI- MS and fluorescence spectroscopic techniques. Their purity was assessed by elemental analysis. Cytotoxicity was tested against five human cancer cell lines using the sulphorhodamine B (SRB) assay, where one of the complexes, 1, 3-bis {biacetyl-2′-(4 ″ ...