Elliptically shaped (Pb1-xCdx)S nanoparticles (NPs) of average size 2.3 x 2.9 nm (minor axis x major axis) have been prepared via reaction of a solid [oligo(p-phenylene-ethynylene) dicarboxylate]Pb0.9Cd0.1 salt matrix, with gaseous H2S. A significantly long emission lifetime, with multi-exponential behavior, is detected in time-resolved photoluminescence measurements, substantially different from the decay patterns of pure PbS and US NPs within the same organic matrix. Evidence for the co-existence of Cd and Pb within the same particle is provided by light-induced X-ray photoelectron spectroscopy.