The electrochemical behavior of the 3-(4-N-pyridine-2-yl benzene sulfonamide azo)-1-nitroso naphthol reagent and its complex with Co (Ⅱ) has been studied at glassy carbon disk electrode in different supporting electrolyte at concentration 1 mol and scan rate (100 mV/s). 3-(4-N-pyridine-2-yl benzene sulfonamide azo)-1-nitroso naphthol was used for enhance the properties of nano cobalt oxide by ligand exchange reaction on nanoparticles.