In this report new PPV-PPE copolymers <b>DE 69, DE 11</b> were compared with the state of the art materials <b>MDMO-PPV</b> and poly(3-alkylthiophenes) (<b>P3DDT, P3OT</b>). The optical band gap energy of the two copolymers <b>DE 69, DE11</b> is somewhat higher than that one of <b>MDMO-PPV</b>. The electrochemical band gap was found to be lower for <b>DE 69, DE11</b> related to for MDMO-PPV. The absorption coefficient of the new PPV-PPE copolymers is higher than for <b>MDMO-PPV</b> but in the same order of magnitude. Films from composites of <b>MDMO-PPV/PCBM</b> and <b>DE69</b> or <b>DE11</b> with <b>PCBM</b> show a clear photoluminescence quenching effect. At 77 K two kinds of LESR signals were identified, one of polarons (<i>P</i><sup>+.</sup>) and one of radical anions of fullerenes. The LESR results show strong differences in kinetics between the separation and recombination processes of photoexcited charge carriers. The relaxation rates of paramagnetic centers were estimated by microwave power saturation experiments. Photovoltaic devices were prepared under ambient conditions on flexible PET-ITO foils with <b>MDMO-PPV/ PCBM</b> (1:3 wt. %) with η<sub>AM1.5</sub> = 2.4% and <b>DE 69/ PCBM</b> (1:3 wt. %) with η<sub>AM1.5</sub> = 1.75% (A=0.25 cm<sup>2</sup>, P<sub>in</sub> = 100 mW/cm<sup>2</sup>).