We have fabricated ultrathin multilayer films via spin self-assembly quickly and easily, using cationic polyp-phenylene vinylene) (PPV) precursor, and as its counterparts, anionic polystyrene-4-sulfonate) (SPS) and dodecylbenzenesulfonate (DBS). The PPV precursor incorporated with DBS could be thermally converted to PPV rapidly at a relatively lower conversion temperature than the self-assembled (PPV precursor/SPS) film. When we thermally converted an alternating multilayer film of [(PPV precursor/ SPS)(5)(/(PPV precursor/DBS))(5)], at a low temperature (110 C), more converted PPV with longer conjugation length (PPV/DBS) and less converted PPV with shorter conjugation length (PPV/SPS) coexisted. As a result, the multilayer film with the different energy band-gaps could be fabricated by thermal-converting an alternating multilayer film at a low conversion temperature in a relatively short time. UV/VIS absorption spectra and photoluminescent spectra demonstrated not only the structural regularity and reproducibility of this system but also the energy transfer between the layers with different conjugation lengths. 2004 Elsevier B.V. All rights reserved.