Co(II) complexes of Schiff base 2-amino-4-nitrophenol-N-salicylidene with some amino acids were synthesized. The Schiff base and its mixed ligand complexes, in general, were non-hygroscopic and stable solids. The structural characterization of Schiff base and cobalt complexes were done on the basis of their melting point, solubility, elemental analyses, conductivity measurements, GC-MS, FTIR, NMR, UV-Visible spectroscopy, magnetic susceptibility, and X-ray diffraction studies. The morphology of mixed ligand Co(II) complexes was studied by scanning electron microscopy. The compounds were subjected to simultaneous thermogravimetric analysis to study their decomposition mechanism and thermal stability. The Schiff base and mixed ligand complexes were preliminary scanned against various strains of microbes to study their biological effect.