A series of bioactive cobalt(III) complexes were synthesized with bidentate ligand have been investigated as vitamin B12 models. The experiment was two pot snythesis, in the first part was green microcrystalline dihalo(dimethylglyoximato)cobalt(III) and second part was brown microcrystalline halo(pyridine based ligand) cobaloximes. Final part of synthesized complexes was characterized by IR, electronic and NMR spectral studies. Infrared spectra of metal complexes indicated the formation of Co-N axial bond and Co-N equatorial bond. Thermal analysis revealed that the Co(III) complexes were stable up to 350 ºC. The experimental results of antimicrobial were showed good zone of inhibition towards selected microbes.