Abstract Mixed ligand complexes of Ni(II) ion with 1,1-dicyanoethylene-2,2-dithiolate (i-MNT 2−) as a primary ligand and o -phenylenediamine (OPD), pyridine (py), α-picoline (α-pic), β-picoline (β-pic) or γ-picoline (γ-pic) as secondary ligands have been isolated and characterized on the basis of analytical data, molar conductance, magnetic susceptibility, electronic and infrared spectral studies. The molar conductance data reveal that most of the complexes have 1:1 electrolytic nature in DMF solution. Magnetic and electronic spectral studies suggest square planer and octahedral stereochemistries around Ni(II) ions. Infrared spectral studies suggest bidentate chelating behaviour of i-MNT2− ion and OPD while other ligands show unidentate behaviour in their complexes.