Layer-by-layer electrostatic assembled Fe-3TRPyP/CuTSPc supramolecular films constituted by homogeneously dispersed electrochemically active columnar structures, about 15 nm high, were obtained and characterized. They are redox conductors acting as rectifiers in the presence of redox species in solution, providing an excellent electrocatalyst for both oxidation and reduction of nitrite and sulfite. The spectroelectrochemical characterization of the supermolecular porphyrin in solution (-2.6 to 2.3 V) revealed I I redox processes involving up to 26 electrons, allowing further applications of the thin films as multi electron-transfer catalysts and active materials for molecular devices. (c) 2006 Elsevier Ltd. All rights reserved.