1. Metallocenyl thioketones of the ferrocene and cymantrene series are capable of replacing the CO ligands in transition metal complexes and function as two-electron ligands to give donor-acceptor bonds of the sulfur atom with the transition metals (S→M). The reaction was used to synthesize some heterometallic binuclear complexes. 2. We obtained and characterized eight new heterometallic binuclear complexes with metallocenyl thioketones and two mononuclear complexes with Michler's thioketone and 4-p-tolyl1,2-thiol-3-thione as the η2-ligands.