With a bistridentate Schiff-base ligand, N',N'(3)-bis[(1E)-1-(2-pyridinyl)ethylidene)] isophthalohydrazide (H(2)L), a [2x2]G grid complex, [Ni(4)(HL)(4)](ClO(4))(4).4H(2)O.0.5 CH(3)OH (1) has been synthesized and characterized spectroscopically and crystallographically. Spectrometric titrations, ethidium bromide displacement experiments, circular dichroism spectral analysis and viscosity measurements indicate that the compound 1 strongly binds with calf-thymus DNA, presumably via intercalation mechanism. Furthermore, the antioxidant activity (superoxide and hydroxyl radical) of the ligand and its nickel(II) complex is determined by using spectrophotometer methods in vitro. Complex 1 is found to possess potent antioxidant activity and be better than standard antioxidants like mannitol.