Pseudo first order reaction kinetics and binding studies of trans-[Co(en)2(CH3CH2CH2)H2O]2+ complex with imidazole ,substituted imidazoles, glycine and ethyl glycine ester has been investigated using spectrophotometric technique. Equilibrium constants were determined as a function of pH at 25°c. Binding and kinetic studies were correlated based on basicity, steric hindrance. From the equilibrium data, it is found that the entering nucleophile is participating in the transition state, thereby SN1 mechanism is proposed. The effect of the incoming ligands on the complex is studied by molecular mechanics. The interaction of trans-[Co(en)2(CH3CH2CH2)H2O]2+with CT DNA has been studied spectrophotometrically.