The electrochemical and spectroelectrochemical properties of the μ-meso(tetrapyridyl)porphyrin iron(III)-tetrakis-{bis(bipyridine)(chloro)ruthenium(II)} complex and of its corresponding μ-oxo dimer have been investigated. Strong Fe–Fe interaction in the μ-oxo dimer has been evidenced by the cathodic shift of the Fe III/II porphyrin redox potential, by more than 0.9 V in comparison with the monomer species (+0.16 V). Electrostatically assembled films constituted by alternating layers of cationic tetraruthenated and anionic tetrasulphonated iron porphyrins have been elaborated and employed in modified electrodes. These films exhibit the characteristic electrochemical waves associated with the Fe III/II porphyrin and Ru III/II (bipy) 2 Cl moieties.