A new series of complexes of the type, [WO(NCS)4 L-L] (where L-L are amine substituted biologically active Schiff bases with general formula , R1N = CHR2. Here R1 is 4-aminosalicylic acid & R2is 4-chloro-benzaldehyde, 2- chloro-benzaldehyde, salicyladehyde, vanillin and benzaldehyde) have been prepared by reaction of ammonium tetra-isothiocyato-oxotungstate(VI) with the corresponding ligand in aqueous medium in the presence of hydrochloric acid. The complexes have been characterized by elemental analysis, molar conductivity, magnetic susceptibility, infrared spectroscopy and 1HNMR spectroscopy. The metal complexes have been screened for their biological activities against bacteria Micrococcus luteus, Enterococcus faecalis, Alcaligenes denitroificans & Klebsiella pneumoniae. The metal complexes show more potent activities compared with Schiff base ligands.