A molecular dispersed heterojunction solar cell consisting of a polymer and dye coated carbon nanotubes blend sandwiched between metal electrodes has been developed. The dye naphthalocyanine (NaPc) was used as the main sensitiser, while nanotubes and poly(3-octylthiophene) (P3OT) act as the electron acceptor and the electron donor, respectively. The incorporation of the NaPc in the P3OT/SWNT composite does dramatically increase the layer absorption resulting in a much higher photocurrent. We report on the exploration of new principles and concepts to develop molecular electronic devices for low cost solar cells. (C) 2003 Elsevier B.V. All rights reserved.