A novel diphenylfluorene-based Cardo copolyimide containing perylene (PFB5) was designed and synthesized by polycondensation of a diamine 4,4'-(9H-fluoren-9-ylidene)bisphenylamine with perylene dianhydride and another dianhydride in m-cresol with isoquinoline as a catalyst at 200degreesC. PFB5 was characterized by FTIR, EA, GPC, TGA, DSC, UV-vis, and PL. Because of the existence of the bulky diphenylfluorene units in the backbone, PFB5 showed high thermal stability and good solubility in common solvents such as chloroform. Solubility of PFB5 in low boiling point solvents allows direct spin coating of the polymer films, which exhibit intense photo- and electroluminescence (EL) in the visible range. This nonconjugated polymer could be used as emitting and electron-hole transporting layers in polymer electroluminescent devices (PELDs). EL properties of the unilayer ELDs based on PFB5 are discussed. The device emitted a greenish yellow light. (C) 2003 Wiley Periodicals, Inc.