We present a comparative study of optical and electronic properties for PbS nanocrystals and Au-PbS core-shell nanostructures. In Au -PbS nanostructures, we observed two nontrivial synergistic effects: (i) extinction enhancement due to coupling of surface plasmon resonance in the Au core to the excitonic states in the Table of Contents Wournal Home PagelSearch the Journals semiconducting PbS shell, and (ii) strong p-type electronic doping of Au-PbS nanocrystal solids that we explained by the intraparticle charge transfer between the PbS shell and the Au core.