The tridentate schiff base, salicylidene imino-o-thiolbenzene, has been synthetized from salicylaldehyde and o-amino thiolbenzene by Duff reaction. The schiff base has been reacted with Cu(II), Ni(II), and Zn(II), to form new complexes; Cu(II)$[C_{13}H_9ONS]{cdot}3H_2O$, Ni(II)$[C_{13}H_9ONS]{cdot}3H_2O,;Zn(II)[C_{13}H_9ONS]{cdot}3H_2O$ It appears that the Cu(II)-complex has tetra-coordinated configuration with the schiff base and one molecule of water, while the Ni(II) and Zn(II)-complexes have hexacoordinated configuration with the schiff base and three molecules of water. The mole ratio of tridentate schiff base ligand to metals was 1:1. These complexes have been identified by infrared spectra, visible spectra, TGA, DTA and elemental analysis.