The solid complexes of Cu(II), Ni(II), Co(II), Mn(II) and Fe(III) with asymmetrical tetradentate Schiff bases derived from o-phenylenediamine (H2L1)/4-methyl o-phenylenediamine (H2L2), 3-Acetyl-6-methyl-pyran-2,4-dione (Dehydroacetic acid) and 2-hydroxy-1-naphthaldehyde have been synthesized and characterized by elemental analysis, conductometry, magnetic susceptibility, uv-visible, i.r, 1H-nmr. spectra, X-ray diffraction, thermal analysis, and screened for antimicrobial activity. The IR spectral data suggest that the ligand behaves as a dibasic tetadentate ligand with ONNO donar atoms sequence towards central metal ion. From the microanalytical data, the stoichiometry of the complexes has been found to be 1:1 (metal: ligand). The physico-chemical data suggests square planar geometry for Cu(II) and Ni(II) complexes and octahedral geometry for Co(II), Mn(II) and Fe(III) complexes respectively. The x-ray differaction data suggests orthorhombic crystal system for Cu(II) complex, monoclinic crystal system for Ni(II)and Fe(III). Thermal behaviour (TG/DTA) of the complexes was studied and kintic parameters were determined by Horowitz-Metzger and Coats-Redfern method. The ligand and their metal complexes were screened for antibacterial activity against Staphylococcus aureus and Escherichia coli and fungicidal activity against Aspergillus Niger and Trichoderma.