The self-assembled monolayers (SAMs) of dinuclear Fe complexes with the dinucleating ligand were prepared. Although these types of dinuclear Fe complexes were able to bind dioxygen in non-aqueous solution at low temperature (-30 ºC), the SAMs of these diiron complexes indicated the dioxygen-binding ability in aqueous solution at room temperature. These dinuclear Fe complexes were very stable by the modification onto Au electrode surfaces. Furthermore, the SAMs showed the reversible binding/releasing to dioxygen in aqueous media and the electrocatalytic activation of the binding dioxygen.