Composites of CdSe and ZnO nanocrystals with conducting polyaniline have been prepared and investigated by optical spectroscopic method. A decrease in nanocrystal photoluminescence has been observed with the increase in the concentration of the polymer in the composites. The study shows that polyaniline causes the quenching of the nanocrystal luminescence. (c) 2006 Elsevier B.V. All rights reserved.