A strategy was described for one-step synthesis and self-organization of polypyrrole (PPy) ultrathin films inlayed with Prussian blue (PB) nanoparticles. The formation of ultrathin films is induced by a drop of toluene solution on aqueous surface, and the organization process is accompanied by the shrinkage of organic layer area on water surface due to the evaporation of toluene. On the one hand, the combination of the downward gravity force from the toluene solution of pyrrole and its upward buoyancy force drives the toluene solution of pyrrole to collapse downwards and scatter outwards on water surface. On the other hand, the strong adhesion ability of PPy and the hydrophobic action between the toluene solution of pyrrole and water drives the upper organic layer to reunite. In addition, the dispersion of toluene solvent toward pyrrole monomers and the retraction of its evaporation kinetics toward the produced PPyPB nanocomposites play a great role here. All of these forces yield a close-packed ultrathin PPy films with inlayed PB nanoparticles. The suggested strategy for preparing ultrathin films of PPy inlayed with PB nanoparticles is very simple. Due to the existence of PPy, the obtained composite films could be easily transferred and anchored onto the solid surface. (C) 2011 Elsevier B.V. All rights reserved.