A new polyphenylene-co-furan (PPF) and a polyhenylene-co-thiophene (PPT) have been synthesized utilizing the Stille coupling reaction and their luminescence properties characterized. The UV-vis, electroluminescence (EL), photoluminescence (PL), and current-field II-Fl characteristics, as well as the stability of the emission of light, were studied in detail for both polymer LED devices. Comparisons of the EL and PL characteristics between PPT and PPF suggest that the quantum efficiency of PPF is higher than that of PPT. However, it was also found that PPF is photochemically unstable and its electroluminescent intensity decays faster than that of PPT.