Schiff base hydrazone chloro-acetic acid[1-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-ethylidene]-hydrazide (HL) and its transition metal(II) complexes of type ML2 [where M= Co(II), Ni(II), Cu(II) and Zn(II)] have been synthesized and characterized on the basis of spectroscopic techniques (IR, NMR, electronic, ESR & mass) and magnetic susceptibility measurements. The physicochemical studies revealed that Schiff base hydrazone acted as monobasic tridentate ligand ONO coordinating through oxygen of hydroxyl group, azomethine nitrogen and carbonyl oxygen to divalent metal ion forming complexes with octahedral or distorted octahedral geometry. Schiff base ligand and its metal complexes have been tested for in vitro antimicrobial activity data against Gram positive bacteria Bacillus subtilis, Micrococcus luteus, Gram negative bacteria Pseudomonas aeruginosa, Pseudomonas mendocina and fungi Verticillum dahliae, Cladosporium herbarium, Trichophyton soudanense using different concentration of ligands and their complexes (25, 50, 100, 200 μg/mL). Streptomycin and Fluconazole were used as a standard drug for antibacterial and antifungal activity respectively. All synthesized compounds showed promising antimicrobial activities against tested organisms and complexes have enhanced activity as compared to the parent ligand.