A new series of Mn(II), Co(II), Ni(II), Cu(II), Cr(III) and Fe(III) complexes with tetradentate unsymmetrical Schiff base ligand derived from o-hydroxyacetophenone, 5-chloro-2-hydroxyacetophenone and ethylenediamine have been reported. The complexes have been characterized by elemental analyses, magnetic susceptibility measurements, electronic and infrared spectra and thermogravimetric analyses. The ligand and its complexes were screened for their antimicrobial  activities against the bacteria Staphalococcus aureus, Bacillus Subtilis, Salmonella typhimurium and Escherichia coli and fungi Aspergillus oryzae and Fusarium species. The results indicated that the complexes exhibited good antimicrobial activities.