Escherichia coli, Klebsiella species, Staphylococcus auerus, Pseudomonas aeruginosa and Neisseria gonorrhoeae. The complex of the type ML1L2 [M= Co (II), L1= thiosemicarbazide and L2= chloroquine] was formed. The complex was non-electrolyte in methanol. The resulting complex was characterized by conductivity measurements and spectral studies. The mixed ligand used act as a neutral tridentate compound with tentative octahedral geometry with metal ions. The findings, using the chemical, spectroscopic analysis and physical properties showed that the ligand employed in this work coordinated to metals in 1: 1: 1 metal-ligand 1-ligand 2. The antibacterial activity was also carried out. The results showed that the complex possesses greater biological activity against the bacterial used and the metal complex possesses greater biological activities than the parent compounds. Thus, they could be promising candidates for novel drugs in pharmaceutical research.