The new dinuclear mixed valence [Mn I I Mn I I I (BPBPMP)(OAc) 2 ]BF 4 complex with the unsymmetrical polydentate ligand 2-bis[{(2-pyridylmethyl)-aminomethyl}-6-{(2-hydroxybenzyl)(2-pyridylmethyl)} -aminomethyl]-4-methylphenol (H 2 BPBPMP) was synthesized. The complex has an Mn I I Mn I I I (μ-phenoxo)(μ-OAc) 2 core and was structurally, IR and UV-Vis spectroscopically and by cyclic voltammetry characterized. The reactivity towards H 2 O 2 shows a catalase-like activity.