Composite materials. based on single-walled carbon nanotubes and a poly(p-phenylene vinylene) derivative. show an interaction between the components capable of solubilising the nanotubes, which has not been otherwise achieved. Here these materials are characterised by electron microscopy, and optical and vibrational spectroscopy. The spectroscopic behaviour of the polymer is seen to be dramatically affected, which is attributed to conformational changes due to the effect of the nanotubes.