Bimetallic Ag/Au prisms (Figure, top) and corrugated core-shell nanoparticles (Figure, bottom) are synthesized using seed-mediated growth. The sizes and shapes of these core-shell nanoparticles are tailored by varying the stoichiometric Au3+/Ag+ ratio. Decreasing Au3+/Ag+ ratio results in nanoparticles with thicker gold shells and roughened surfaces, and surface plasmon bands that are red-shifted to the near-IR region of the electromagnetic spectrum.