Poly(3-perfluorooctylthiophene) is the first reported conjugated polymer that is soluble in supercritical carbon dioxide (see Figure). The electron-withdrawing nature of the perfluoroalkyl groups affords a material that undergoes reversible reduction (n-doping), and the polymer displays a large Stokes shift because of a large difference in the conformation of the ground state and a more planar excited state.