Vanadyl and zinc (II) complexes with VO (O 2 S 2) and Zn (O 2 S 2) coordination mode, respectively, were synthesized. Among them, bis (1, 4-dihydro-2-methyl-1-phenyl-4-thioxo-3- pyridinolato) zinc (II) complex exhibited an extremely high insulin-mimetic activity (IC 50= 0.04 mM when IC 50 value of a positive control, VOSO 4 was estimated to be 1.0 mM) compared to vanadyl and zinc (II) complexes reported previously.