Interaction between vanadium pentoxide and bioactive Schiff–bases led to the formation of vanadium (III/IV) complexes. Ten complexes have been characterized using mass, IR, UV-VIS and ESR spectra, magnetic moments and conductance measurements as well as elemental and thermal analyses. Magnetic moments and ESR measurements confirmed vanadium complexes have (III/IV) oxidation state. Conductivity measurements indicate that complexes are not electrolytes. A representative set of vanadium (III/IV) complexes in varying coordination environments have been tested as anti-hyperglycemic agents against type 2 diabetes mellitus in concentration doses (30 and 100 µM/Kg) using female albino rats. The pharmacological data showed that, complexes 1 and 8 produced significant decrease in blood glucose level. Furthermore, these two complexes showed an improvement in liver and kidney function after daily administration for two weeks.