Hybrid multilayer films composed by osmium metallopolymer [Os(bpy)(2)(PVP)(10)Cl]Cl (Os-poly) and europium phosphomolybdate, K11[Eu111(PMo11 O-39)(2)] (Eu(PMo11)(2)), were prepared using the electrostatic layer-by-layer (LbL) self-assembly method. The film build-up, monitored by electronic spectroscopy, showed a regular stepwise growth indicating a strong interaction between layers. The XPS measurements corroborated the successful fabrication of the hybrid films with the Os-poly/Eu(PMo11)(2) composition. SEM images revealed a completely covered surface with a highly roughened texture. Electrochemical characterisation of films by cyclic voltammetry revealed three Mo-based reduction processes (Mo-VI -> Mo-V) in the potential range between -0.4 and 0.1 V and one Os reduction process (Os-III -> Os-II) at approximate to 0.270 V. The cyclic voltammograms of two electroactive probes, [Fe(CN)(6)](3-/4-) and [Ru(NH3)(6)](3+/2+) on {Os-poly/ Eu(PMO11)(2)}(n) modified electrodes revealed redox mediation between film and the probes. Furthermore, the {Os-poly/Eu(PMO11)(2)}(n) multilayer films also showed excellent Mo-based electrocatalytic activity towards reduction of nitrite and iodate, confirming the multi-functional properties of the hybrid europium phosphomolybdate - osmium metallopolymer LbL films. (C) 2014 Elsevier Inc. All rights reserved.