A simple and convenient method, free of any template, has been proposed to synthesize hollow Ag2S semiconductor with a novel network-like microstructure under hydrothermal conditions with AgNO3, thiourea (Tu) and hydrochloric acid as reagents, The ratio of AgNO3 to Tu, the reaction temperature and the addition of hydrochloric acid are of importance to the formation of the hollow network-like microstructure. (C) 2002 Elsevier Science B.V. All rights reserved.