Synthesis of some novel oxidomolybdenum(V) and dioxidomolybdenum(VI) complexes with a Schiff base, (2,4-dihydroxy acetophenoneisonicotinoylhydrazone) (DAIH), derived from 2,4-dihydroxy acetophenone and isonicotinoylhydrazide are reported. The complexes have been characterized by elemental analyses, molar conductance, magnetic susceptibility data, IR, UV-Vis, EPR, H-1 NMR and FAB mass spectral studies. The physico-chemical studies and spectral data indicate that the ligand (DAM) acts as a monovalent tridentate chelating agent. The FAB mass and X-band EPR spectra indicate that the pentavalent Mo in the complex is monomeric in nature. The X-ray diffraction studies of the complex [MoO(DAIH)Cl-2] correspond to orthorhombic crystal lattice with unit cell dimensions a = 16.64 angstrom, b = 13.25 angstrom and c = 9.56 angstrom. All the complexes are found to be neutral with distorted octahedral geometry. The thermal behaviour of the complex [MoO(DAIH)Cl-2] was investigated by thermogravimetric techniques. The ligand (DAM) and its two complexes [MoO(DAIH)Cl-2], [MoO2(DAIH)Cl] were screened for their in vitro antibacterial activity. The complexes exhibited higher activity than the ligand (DAIH). The 3D molecular modeling and analysis for bond length and bond angles have also been carried out for one of the representative compounds, [MoO(DAIH)Cl-2].