We have fabricated the polymeric light-emitting diodes (PLEDs) with new synthesized blue-emitting polymers, poly(phenyl-9, 9-dioctyl-9', 9'-dihexanenitrile) fluorene (PPFC6N) and polymer blending of PPFC6N and polyfluorene (PFO). Our devices show a real blue emission for both polymers, showing the electroluminescence (EL) spectra near 445 nm, with relatively low turn-on voltage of polymer blend compared with that of PPFC6N. However, a slight blue shift occurred for PPFC6N when a 10nm thick hole-blocking molecule, oxadiazole derivative, was introduced in the PLEDs. (c) 2005 Published by Elsevier B.V.