Phthalylsulphathiazole (PST) is a biologically active, monodendate neutral ligand. The present study reveals the microwave assisted preparation, physico-chemical, spectral and biological characterization of Co(II), Ni(II) and Cu(II) complexes with PST and benzoate ion (ben) ligands. The molecular formulae of the complexes were arrived at from the estimation of metals, electrical conductivity, and magnetic moment (μeff) values. The IR spectral data confirm the entry of the ligands into the coordination sphere. The electronic spectral data indicate the probable geometry of the complexes. The antimicrobial and anti fungal screening of the complexes against the bacteria viz., Staphylococcus sp., Escherichia coli, Proteus vulgaris, Shigella flexneri and Lactobacillus pulgaricus and fungi viz., Candida albicans, Aspergillus oryzae, Aspergillus niger, Aspergillus flavus and Aspergillus sojae were carried out by well diffusion method. The results indicate that Ni(II) complex exhibits enhanced antibacterial activity against Escherichia coli, Proteus vulgaris, Shigella flexneri and Lactobacillus pulgaricus than the pure ligands. Co(II) and Cu(II) complexes have high antibacterial activity against Staphylococcus sp. All the complexes show high anti fungal activity against Candida albicans, Aspergillus oryzae, Aspergillus niger, Aspergillus flavus and Aspergillus sojae. The diphenylpicrylhydrazyl free radical scavenging activity of the above three complexes are found to be nominal.