Zn (II) and Cd(II) complexes of the tridentate Schiff base ligand 3-(2-(2-hydroxybenzylidene)hydrazinyl) quinoxalin-2(1H)-one(L) have been synthesized and characterized by 1H-NMR,IR, UV-Visible, Mass spectroscopy and CHN analysis data. The ligand (L) formed 1:2 complexes, ML2 with M=Zn(II) and Cd(II) and behaved as O,N,O-tridentate ligand. The complexes were found to be fairly stable. The interaction of the complexes with Calf Thymus DNA was investigated by UV spectroscopic studies and the intrinsic binding constant, Kb values are calculated. The base binding constants of the DNA with Zn(II) and Cd(II) complexes were found to be 7.18 × 105 and 8.18 × 109 M-1 respectively.