The powdered samples of CuInS2-, obtained by a chemical synthesis method and contained either thread-like or belt-like nanowires were studied by a spectroscopic phase-modulated ellipsometer in the photon energy range from 0. 8 to 6 e Vat room temperature. The samples with thread-like and belt-like nanowires were found to have different pseudodielectric function, which was closer to that of bulky single crystalline CuInS2 in the case of belt-like nanowires. The same value of energy gap revealed by incoherent ellipsometric approach to bulky samples and samples with nanowires was accounted for the presence of some fraction of bulky phase in the nanostructured samples. Reliability of the obtained data and relationship between the ground state shape of the nanowires and the electronic spectrum were discussed. It was substantiated that the obtained data provide a first realistic glimpse on electronic spectrum of nanostructured CuInS2. (c) 2005 Elsevier B.V. All rights reserved.