Homoleptic and heteroleptic Ni(II) complexes represented as NiL¹₂ and NiL¹L²L³ (where, L¹ = N-ethyl-N-phenyldithiocarbamato anion, L² = isothiocyanato anion, and L³ = triphenylphosphine) were synthesized. The complexes have been characterized by elemental, IR, NMR, and single-crystal X-ray analysis. The thermal decomposition behaviour of the complexes were studied using thermogravimetric analysis (TGA). The optimized geometry and the electronic analysis of the type of bonding within the complex structures were performed using methods based on the density functional theory and atom in molecule (AIM) analysis method. X-ray structural analysis of both complexes confirms distorted square planar geometry about the Ni atom. The TGA indicates that the complexes belong to the class of volatile dithiocarbamates which yield the corresponding metal sulphide without any intermediate products. Structural parameters from crystallographic and DFT studies have been compared and found to correlate with each other. The small discrepancies in geometric parameters are attributable to H-bonding and packing interactions within the lattice which are not modelled during computational study. AIM analysis suggests that in NiL¹L²L³ , the Ni· · · L interactions are more covalent in nature whereas in NiL¹₂ complex, they are more ionic in character.