Co(II), Ni(II), Cu(II) and Zn(II) complexes with the bidentate ligand 4-[(3-ethoxy-4-hydroxybenzylidene)amino]-3-mercapto-6-methyl-5-oxo-1,2,4-triazine have been synthesized. The Schiff base and its metal complexes have been characterized by various physicochemical techniques like IR, 1H-NMR, ESR, electronic and fluorescence spectroscopy and cyclic voltammetry. Elemental analysis, conductivity measurements and thermal analysis of synthesized compounds were also carried out. All the complexes were colored and non-electrolytic in nature. In vitro biological activities of the ligand and complexes have been checked against some pathogenic gram positive, gram negative bacteria and different fungi and then compared with some standard drugs as control.