Abstract: The synthesis and characterization of benzene and p-toluenesulfonylhydrazones derived from salicylaldehyde and 2-hydroxyl-1-naphthaldehyde and their Ni(II) complexes are reported. The structural investigation of these compounds was based on elemental analysis, magnetic moment and spectral (ultraviolet, infrared and ¹H-NMR). The Ni(II) complexes were diamagnetic. The stoichiometry of all the complexes was found to be 1:2 and the geometry around the nickel ions is square planar. The electrochemical behavior of the Ni(II) complexes was investigated in DMSO by cyclic voltammetry (CV), rotating disc electrode (RDE) and coulometry. The complexes displayed Ni(III)/Ni(II) couples irreversible waves and the substitution of the phenyl by naphthyl fragments causes a negative shift in the formal potential.