A layer-by-layer (LBL) deposition technique based on the electrostatic attraction of oppositely charged species has been employed to fabricate multilayer films consisting of the crown heteropolyanion, K28Li5H7P8W48O184 center dot 92H(2)O ([P8W48](40-)), and the Os2+ functionalised pyrrole monomer, osmium-bis-N,N'-(2,2'-bipyridyl)-N-(pyridine-4-yl-methyl-(8-pyrrole-1-yl -octyl)-amine)chloride (BPPA-Os) on a glassy carbon electrode (GCE) initially modified with a monolayer of 4-aminobenzoic acid. The multilayer films were then characterized by cyclic voltammetry (CV). The films were found to be both uniform and stable, whilst exhibiting good electrocatalytic activity towards both nitrite and hydrogen peroxide. (c) 2007 Elsevier B.V. All rights reserved.