We developed a new method for the fabrication of gold nanoparticles (AuNps) in a poly(vinyl alcohol) film using a two-color two-laser irradiation. The benzophenone ketyl radical (BPH-) in the excited state (BPH-(D-1)) was used as a reducing agent. Although BPH- in the ground state also reduced AuCl4- to produce AuNps, the formation of AuNp was significantly enhanced by the BPH-(D-1) generated by the two-color two-laser irradiation. Because the electron transfer from the BPH-(D-1) to AuCl4- enhanced the formation of AuNps. (c) 2005 Elsevier B.V. All rights reserved.