We report a facile solution route for the synthesis of single-crystalline and hexagonal CuS nanoplatelets by thermolysing single-precursor copper ethylxanthate [Cu(exan)(2)] in hexadecylamine (HDA) at moderate temperature. The morphology and structure of CuS nanocrystals (NCs) are characterized by means of XRD, TEM, HRTEM, SAED and UV-vis absorption spectroscopy. Key synthetic parameters, such as reaction temperature, reaction time and precursor concentration, which have a great influence on the size and shape of the products, have been comprehensively investigated. It was found out that the nanoplatelets are self-assembled into one-dimensional ordered string-like structure under appropriate conditions. The solvent used to disperse the nanocrystals can affect the self-assembly of the CuS nanoplatelets, and polar solvent favors the formation of long strings. The possible mechanisms of forming hexagonal nanoplatelets and self-assembled strings are discussed. (c) 2006 Elsevier B.V. All rights reserved.