An asymmetric, potentially bidentate dioxime ligand (H2L) was formed by condensation of 4-biphenylchloroglyoxime and napthyl-1-amine. Two equivalents of H2L were reacted with CoCl(2)6H(2)O under appropriate conditions with deprotonation of the dioxime ligand. A series of new organocobaloxime derivatives of the type [CoR(HL)(2)Py], [CoRL2PyB2F4], and [CoRL2Py(Cu(phen))(2)] (H2L=4-(napthyl-1-amino)biphenylglyoxime; phen=1,10-phenathroline; R=izopropyl and benzyl; Py=pyridine) were synthesized. The products were characterized by elemental analysis, molar conductance, FT-IR, H-1 NMR, and magnetic susceptibility measurements. Catecholase-like activity properties of all complexes were also studied. All complexes are catalysts for the oxidation of 3,5-di-tert-butylcatechol to 3,5-di-tert-butyl-1,2-benzoquinone in methanol. Antimicrobial activity studies of H2L and the six complexes were carried out on standard strains (human pathogenic) of bacteria (Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Bacillus cereus, Enterococcus faecalis, Streptococcus pneumoniae, Listeria monocytogenes, Bacillus subtilis, Escherichia coli, Pseudominas aeruginosa, Salmonella typhi) and the yeast Candida albicans. The compounds showed a significant inhibition of the growth of the Gram-positive bacteria tested. Among the tested microorganisms, S. aureus was the most sensitive strain, especially to H2L and its complexes.