International Journal for Innovation Education and Research www.ijier.net Vol:-9 No-8, 2021 International Educative Research Foundation and Publisher © 2021 pg. 13 Synthesis, characterization and antimicrobial evaluations of mixed ligand complexes of sulfamethoxazole and metronidazole with some transition metals (Co, Cu and Ni) in water methanol medium Olagboye Sulaiman A*, Senior Lecturer, Department of Chemistry, Ekiti State University, Ekiti State, Nigeria. Sulaiman.olagboye@eksu.edu.ng Bamisaye John Blessing Ekiti State University, Ekiti State, Nigeria. Adesugba Jerome Femi Ekiti State University, Ekiti State, Nigeria. ABSTRACT Sulfamethoxazole and metronidazole are antibiotics use for the treatment of various bacterial infections. Their use as ligand is very prominent in formation of metal complexes. The transition metal complexes are synthesized by reaction of Sulfamethoxazole and metronidazole with metals such Mn(II), Cu(II), Fe(II) and Ni(II). The synthesized metal complexes are tested as antibacterial and antifungal. The antimicrobial activity of the complexes displays good potency against some microorganism such as Xanthomonas axonopodis, Streptococcus faecalia, Salmonella entrica, Claribacter michiganense, Xanthomonas phaseolin for bacteria and S.roofisii, M.phonoides, C.lindimuthianum for the fungi, it is revealed that all copper complexes show stronger antibacterial activity than the free drugs. The spectroscopic properties of the complexes were investigated using UV/visible and FT-IR which show metal-charge from 3d to 3s transition in which the transition state shows that they are octahedral geometry and their coordination site respectively. Their percentage yield was moderately high and producible. The complexes synthesized have higher inhibitory activities than the free ligand. The drug resistance in microbes is resulting in the incompetence of available drugs to care for the infections. The thermal analysis shows that the complexes are stable. Keyword; Sulfamethoxazole, Metronidazole, Antimicrobial, Metal complexes and Spectroscopic study