Abstract A new Ni (II) complex, namely [Ni 2 (OAc) L]· ClO 4· H 2 O, was synthesized by [2+ 2] cyclo-condensation between 2, 6-diformyl-4-methylphenol and N, N-bis (3-aminopropyl)-4- methoxybenzylamine (amba) in the presence of nickel (II) and characterized by spectroscopy, elemental analysis, and X-ray single crystal diffraction. The interactions of the complex with DNA have been measured by spectroscopy and viscosity measurements. ...