The tetraazamacrocyclicdiene ligand, Me6[14]diene (L) on reduction with sodium borohydrate yielded isomeric saturated ligands ‘tet-a’ and tet-b’, whereas 3,10-C-meso-Me8[14]diene (L1) yielded isomers, LA, LB and LC. Reactions of tet-a, tet-b, LB and LC with cobalt(II) perchlorate hexahydrate produced brown μ-peroxo binuclear cobalt(III) complexes corresponding to the molecular formula, [(H2O)L*Co-O-O-CoL*(H2O)](ClO4)4 ( L* = ‘tet-a’, ‘tet-b’, LB or LC). However similar reactions with L, L1 and LA did not produce such type of complexes. The complexes have been characterized on the basis of elemental analysis, spectroscopic, magnetochemical and molar conductivity data. The antibacterial activities of the ligands and their complexes have been investigated.