Substitution reactions of benzyl(aquo)cobaloxime with O- donor ligands such as urea, acetamide, semicarbazide and formamide have been studied as incoming nucleophiles. These benzyl (Ligand) cobaloximes have been synthesized and characterized on the basis of IR, LC/MS, 1H and 13C NMR spectroscopy. The frequency changes in the IR spectra and shifts in the NMR were explained on the basis of back- donation of electrons from metal to the ligand and the basicity of the ligand. Further equilibrium constants for axial ligation of the benzyl(aquo) cobaloximes have been determined spectrophotometriclly as a function of pH at λmax of 442 nm. Anti-microbial activity of the complexes have been screened in vitro against the microorganisms Escherichia coli. UV-visible scan of trans PhCH2Co(DH)2H2O with different concentrations of the ligand has been studied. The interaction of benzyl(ligand)cobaloxime with CT-DNA has been studied spectrophotometerically and binding constant has been calculated.