Benzyl(aquo)cobaloxime has been prepared upon reacting this aquo complex with different N donor ligands (pyrazole, dimethyl pyrazole, alanine, alanine methyl ester and alanine ethyl ester) gives benzyl(ligand)cobaloxime [PhCH2Co(DH)2L]. Determination of equilibrium constant of the benzyl(aquo)cobaloxime with the above mentioned ligands as a function of pH at 25ºC, 1.0M ionic strength (KCl) by using spectrophotometric techniques. The rate of substitution of H2O varies with the pka of the incoming ligand. The equatorial plane consists of four N atoms, two each from the dimethylglyoxime ligands, while the two axial positions are occupied by benzyl and neutral N donor base ligand The characteristic absorption band of ν(C=N) of dimethylglyoximato ligand in the benzylcobaloximes shifts to lower wave numbers as the donating power of the base ligand increases. The formation of benzyl ligand cobaloximes is confirmed on the basis of elemental analysis UV-Visible absorption spectroscopy, IR, 1H, 13C NMR spectra as well as LC⁄MS analysis. Binding of these complexes with calf thymus DNA (CT-DNA) has been investigated by absorption spectroscopy, steady-state emission spectroscopy and viscosity measurements. The experimental results indicate that the size and shape of the intercalating ligands have marked effect on the binding affinity of the complexes to CT-DNA. The complex [PhCH2Co(DH)2PY] binds with CT-DNA through an intercalative binding mode.