The recent developments on organic photovoltaic cells using covalently linked fullerene-(pi-conjugated oligomer) ensembles as the active layer are reviewed. This molecular approach appears to be particularly interesting since the bicontinuous donor-acceptor network obtained by chemically linking the hole-conducting moiety to the electron-conducting fullerene subunit prevents any problem arising from bad contacts at the junction, as observed for polymer/C-60 blends. Furthermore, the behavior of a unique molecule in a photovoltaic cell and the study of its electronic properties means one can easily obtain the structure/activity relationships leading to a better understanding of the photovoltaic conversion. Finally, this new synthetic approach offers great versatility for design tuning of the photovoltaic system. (C) 2004 Elsevier B.V. All rights reserved.