A series of six coordinated adducts of bis(tertiarybutylthioxanthato)nickel(II) with general formula [Ni(S2CSC4H9)2(L)2] (Where L = ethylpyridines and chloropyridines) were synthesized and characterized by elemental analysis, molar conductivity measurements, magnetic susceptibility measurements, TGA-DTA , mass, IR and UV spectroscopy. All the adducts have 1:2 stoichiometry, are non ionic and paramagnetic in nature. TGA-DTA studies show the formation of NiS as the stable end product of the decomposition. The electronic and magnetic susceptibility studies are consistent with the distorted octahedral geometry for the adduct. Antifungal activities of these adducts have been carried out against the fungal strain Sclerotium rolfsii.