The reaction of potassium N-(methanesulfonyl)-dithiocarbimate, K-2[S2C=NSO2CH3], with nickel(II) chloride hexahydrate, NiCl2 . 6H(2)O, formed the complex anion bis(N-(methanesulfanyl)dithiocarbimate)nickelate(II) [Ni(S2C=NSO2CH3)(2)](2-), which was isolated as its tetra-n-butylammonium salt. The UV-Vis data obtained were consistent with the formation of a nickel-sulfur diamagnetic planar complex. The H-1 NMR and the C-13 NMR spectra showed the expected signals for the n-Bu4N+ cation and the dithiocarbimate moiety. The single-crystal structure analysis showed that tetra-n-butylammonium bis(N-(methanesulfonyl)-dithiocarbimate) (Bu4N)(2)[Ni(S2C=NSO2CH3)(2)], crystallizes in the monoclinic space group P2(1)/c with a = 9.3197(5), b = 15.0795(8), c = 17.5286(9) Angstrom, beta = 91.262(3)degrees, V = 2462.8(3) Angstrom(3), and Z = 2. The nickel atom is coordinated to four sulfur atoms.