A series of new stable adducts of tris (pentafluo-rophenyl)antimony(V) diisothiocyante of the type (C6H5)3 Sb(NCS)2.L. Where, L = dipropyl formamide (DPF), 3-methylpyridine(3-Picoline), dimethyl formamide (DMF), tryphenylphosphine oxide(Ph3PO), triphenylarsine oxide (Ph3AsO), dimethyl sulfoxide (DMSO), thiourea (TU), pyridine(C5H5N) have been synthesized by the reaction of tris (pentafluorophenyl)antimony(V) diisothiocyanate with desired ligand in anhydrous methanol. Tris(pentafluorophenyl) antimony diisothiocyanate was obtained by the metathetical reaction of tris(pentafluorophenyl) antimony (V) dichloride and potassium thiocyanate in anhydrous methanol. The molecular weight measurement and molar conductance data of the complexes revealed them to be monomeric and non-conducting in nature. Elemental analysis and IR data indicates that the complexes have hexacoordinated octahedral structure.