Communication: A novel material for molecular optoelectronics consisting of a composite of carbon nanotubes and poly(m-phenylenevinylene-co-2,5-dioctoxy-p-phenylenevinylene) (PmPV) is reported. Incorporation of the nanotubes is demonstrated to increase the electrical conductivity of the polymer by up to eight orders of magnitude. The nanotubes appear to act as nanometric heat sinks, preventing the build up of large thermal effects, which degrade these conjugated systems. It is also shown that the composite can be used as the emissive layer in an organic light-emitting diode, which promises future applications in optoelectronics.