The fluorescence of pyrene species covalently linked with a methanofullerene is nearly completely quenched due to efficient excited-state energy transfer to the fullerene cage, resulting in the population of the emissive fullerene excited state. The quenching is largely static in nature, consistent with the computational result that the pyrene moieties are close to the fullerene cage. The yield for the excited-state pyrene to fullerene energy transfer is determined. (C) 2003 Elsevier Science B.V. All rights reserved.