Phase pure wurtzite ZnS nanoribbons were synthesized by a simple thermal evaporation process. Scanning electron and transmission electron microscopic observations revealed that the nanoribbons were smooth and uniform throughout their length and perfectly single crystalline with wurtzite ZnS structure. On the other hand, bicrystalline ZnS nanoribbons were achieved by increasing the flow rate of the carrier Ar gas. The growth mechanism was found to be conventional vapor-solid process. The microstructural studies indicate that in addition to its role as carrier gas, the flow rate of the Ar gas can affect the size and shape of the ZnS nanostructures fabricated by vapor-solid method. Optical absorption spectrum revealed the nanoribbons to be highly transparent in the visible region. Photoluminescence properties of the ZnS nanoribbons were found to be dependent on the growth condition and the resultant morphology. (c) 2005 Elsevier B.V. All rights reserved.