Complexes of Co(II), Ni(II), Cu(II) and Zn(II) with Schiff base derived from 2-hydroxy-5-chloroacetoph enone and 4-(p-hydroxyphenyl)-2-aminothiazole have been synt hesized and characterized on the basis of elemental analysis, Infrared, 1 H NMR, molar conductance, magnetic susceptibilities and thermogravimetric analysis. The Schiff base acts as a monobasic bidentate ligand commonly coord inates through the oxygen atom of phenolic OH group and the nitrogen atom of azomethine group, which is confirm ed by IR spectral data. Thermal analysis indicates the presence of coordinated as well as lattice water molecules i n the complexes which are also confirmed by IR spec tral data. The analysis of diffuse reflectance spectra, magnet ic susceptibility and thermal analysis data indicat e distorted octahedral geometry for Cu (II) complex while octah edral geometry for the Co (II), Ni (II) & Zn (II) c omplexes. All the complexes have been evaluated for their antimic robial activity by agar cup-plate method against v arious organisms.