In this paper, the electrochemical and photophysical properties of two well-solubilized monofunctionalized methanofullerene derivatives (TDC60 and TC60) were investigated by cyclic voltammetry, UV-visible absorption, and fluorescence spectroscopic methods. The two methanofullerenes show almost the same electron acceptor properties. The MEH-PPV/methanofullerene blends were made, and it was found that the photoluminescence of MEH-PPV could be quenched more efficiently by TDC60. The two methanofullerenes were used to fabricate organic photovoltaic devices by taking MEH-PPV as the electron donor. Although the photovoltaic properties of the MEH-PPV/methanofullerene devices are better than those of the pristine MEH-PPV, the MEH-PPV/TDC60 device system shows even better performances. Considering the similarities of the structures as well as the electron acceptor abilities, the better performance of the MEH-PPV/TDC60 photovoltaic device should be due to the better compatibility of TDC60 with MEH-PPV, which was confirmed by AFM investigation.