A fabrication method for submicrometer-wide electric conductive patterns using Ag nanoparticle/polymer composites on furan-functionalized substrates (see Figure) is reported. A 180 nm wide (full width at half maximum) photofabricated pattern has been achieved, well below the wavelength of incident light. After annealing at 200 degreesC for 40 min, the pattern worked as an electric wire with a resistivity of similar to8 x 10(-4) Omega cm.