Nanoparticles of Bi2S3 synthesized at the interface of water and toluene undergo hierarchical assembly yielding nanorods that further aggregate to globules that form a deposit suspended at the interface. The obtained films have been characterized by X-ray diffraction, scanning electron microscopy and high-resolution transmission electron microscopy. The mechanism of growth is ascertained by studying experimental factors that influence this unusual assembly process. (c) 2008 Elsevier B.V. All rights reserved.