This work describes the syntheses of three compounds containing [Ni(RSO 2 NCS 2 ) 2 ] 2− anions: (Bu 4 N) 2 [Ni(CH 3 CH 2 SO 2 NCS 2 ) 2 ] (1), (Bu 4 N) 2 [Ni(4-IC 6 H 4 SO 2 NCS 2 ) 2 ] (2) and (Bu 4 N) 2 [Ni(2,5-Cl 2 C 6 H 3 SO 2 NCS 2 ) 2 ] (3). They were obtained in the crystalline form by the reaction of the appropriate potassium N-R-sulfonyldithiocarbimate (RSO 2 NCS 2 K 2 ) with nickel(II) chloride hexahydrate in methanol/water. Elemental analyses were consistent with the proposed formulae. UV–Vis and IR data are consistent with the formation of nickel–sulfur diamagnetic planar complexes. The 1 H NMR and 13 C NMR spectra showed the expected signals for the tetrabutylammonium cation and the dithiocarbimate moieties. Single crystal structure analyses showed that 1 crystallizes in the monoclinic space group P2 1 /n, 2 crystallizes in the monoclinic space group P2 1 /c and 3 crystallizes in the triclinic space group P1¯. In these compounds the Ni atom is coordinated to four S atoms in a distorted square plane geometry due to the asymmetric bidentade chelation by each ligand.