Polyaniline forms a strong complex with chloroaurate at the protonated imine sites. Here we report on an electrochemical procedure that allows preparation of gold clusters by adding gold atoms one-by-one ("bottom-up" approach). It is contrasted with the "top-down" approach in which the growth of multi-atom All clusters was also controlled electrochemically. Our results confirm that both the amount and the size of gold clusters affect the properties of the composite material. (c) 2007 Elsevier B.V. All rights reserved.