A new series of additional complexes of bis(O-butyldithiocarbonato)nickel(II) with ethylpyridines have been prepared and characterized by physicochemical techniques like elemental analysis, molar conductance measurements, TGA-DTA and UVvisible electronic spectroscopy, and IR-spectral data. The structure of [Ni(S 2 COC 4 H 9 ) 2 (C 7 H 9 N) 2 ] has been established by X-ray crystallography. The complex crystallizes in the monoclinic space group P1/n with unit cell parameters a = 14.0721(6), b = 7.0078(2), and c = 15.3604(7)Å and = 90.00, = 108.065(5), and = 90.00∘ . The Ni atom in the title complex is octahedrally coordinated within a trans-N 2 S 4 donor set, with the Ni atom located on a centre of inversion. Crystal structure was solved by direct methods and refined by full matrix least squares procedures to a final -value of 0.0545 for 1984 observed reflections. The butyl chain is disordered over two sets of sites, with occupancy ratio of 0.572 : 0.427.