The interface between water and an organic liquid has been exploited to prepare nanocrystals of US. The technique involves introducing an appropriate precursor of cadmium in the organic layer and the sulfiding reagent in the aqueous layer. The size distribution of the nanocrystals formed at the interface can be controlled by varying parameters such as the reactant concentration, temperature, viscosity of the medium, reaction time and the choice of the reagents. The US nanocrystals have been characterized by TEM, electronic absorption and emission spectroscopy. Nanocrystaline gamma-FeO3 and ZnO can be prepared by taking cupferron complex of the metals in the organic layer and NaOH in the aqueous layer. (C) 2003 Elsevier B.V. All rights reserved.