A new Schiff base Na+L- was prepared by condensation of sodium (3E)-3-hydrazinylidene-3H-1,2- benzoxazole-2-ide-1,1-dioxide with 7-methyl-3-oxo-3,4-dihydroquinoxaline-2-carbaldhyde. The transition metal complexes of Cobalt (II), Nickel (II), Copper (II), Zinc (II) and Cadmium(II) with [L] Schiff base were prepared and fully Characterization on the basis of elemental analysis, 1HMR, Mass spectroscopy, FTIR and electronic spectra, as well as the molar conductivity and magnetic moment measurements were carried out to adopt the Octahedral geometry of [ML X.2H2O], M= Co(II),Ni(II), Cu(II), X=NO3- whereas the geometry of Zn(II) and Cd(II)complexes[MLX], X= Cl- show tetrahedral geometry. The antimicrobial activity of the free Schiff base Na+L- and its metal complexes were screened against two gram positive and two gram negative bacterial Escherichia coli and Staphylococcus aures. It is obtained that the zinc (II) and Cd(II) complexes exhibited the highest inhibition zone in compared with the free ligand.