Schiff bases are a significant class of chelating agents in coordination chemistry because of their versatility and ability to form easy stable complexes with different transition metals. In the last years, interest in Schiff bases derived from sulfonamide antibiotics with transition metal complexes has increased due to their potential applications in chemistry, biology and medicine [1]. New Co(II), Ni(II) and Cu(II) complexes were synthesized with the Schiff base ligand obtained by the condensation of sulfathiazole with salicylaldehyde. They were characterized by elemental analysis, molar conductance, spectroscopic techniques (IR, DRUV), magnetic moments, thermal (TG/DTG/DSC) and powder X-ray diffraction data to explicate their structure. The results obtained showed that the complexes had composition of [ML2]∙nH2O type being nonelectrolytes [2]. The IR data confirmed that the Schiff base ligand is tridentately coordinated to the metallic ions with two N atoms from azomethine group and thiazole ring and one O atom from phenolic group. An octahedral geometry was proposed for the three complexes. TG experiments revealed the thermal stability of metal complexes and confirmed their compositions suggested by the analytical data (Figure). In addition to experimental data molecular modeling study has been made and present the optimized geometries of metal complexes. The powder XRD and SEM studies show that all the complexes are nanocrystalline.The Schiff base and its metal complexes were tested against various types of bacteria.