2-Hydroxy-5-methylacetophenone salicyloyl hydrazone and its Cr (III), Mn(III), Fe(III) and VO(IV) metal complexes were synthesized. Elemental analyses, molar conductance, magnetic moments, electronic, 1H NMR, mass, IR, ESR spectra and thermal studies (TGA & DTA) were applied for characterization. The complexes are coloured solids, air stable, non-hygroscopic and soluble in DMF and DMSO only. IR spectral studies reveal that ligand act as tribasic tetradentate (ONOO) (enol form) donor towards Cr(III), Mn(III) and Fe(III) and dibasic tridentate (ONO) (keto form) donor towards VO(IV) complex. The molar conductivity data of the complex show them to be non-electrolyte. Magnetic susceptibility measurements favour octahedral coordination for Cr (III) and Fe(III) and square pyramidal coordination for Mn(III) and VO(IV). The complexes were treated for TGA and DTA studies. Thermo-kinetic parameters such as activation energy (Ea), order of reaction (n), entropy change (∆S), free energy change (∆F) and apparent entropy change (S*) have been calculated on the basis of TG curve by using the Freeman-Carroll and Sharp-Wentworth methods. ESR spectra of vanadyl complex are recorded and discussed. In addition, the antimicrobial activities of the ligand and its metal complexes were also examined by well diffusion method.