The one-pot synthesis of nanocomposites of a conductive poly(N-vinylcarbazole) (PVK) with CdS, Ag, Pd-50-Ag-50, and Pt-50-Ru-50 nanoparticles was performed with gamma irradiation in a tetrahydrofuran-water mixture (3/1 vol %). For comparison, the CdS, Ag, Pd-50-Ag-50, and Pt-50-Ru-50 nanoparticles were also prepared with gamma irradiation with polyvinylpyrrolidone as a stabilizer. Ultraviolet-visible spectroscopy, transmission electron microscopy, X-ray diffraction analysis, and photoluminescence spectroscopy were used for the characterization of CdS, Ag, Pd-50-Ag-50, and Pt-50-Ru-50 nanoparticles and nanocomposites of PVK with CdS, Ag, Pd-50-Ag-50, and Pt-50-Ru-50, nanoparticles. The absorption spectrum of the CdS-nanoparticle-based composite revealed a quantum confinement effect. The emission spectrum of the composite with CdS nanoparticles and PVK indicated the block effect of PVK for surface recombination. (c) 2006 Wiley Periodicals, Inc.