We have demonstrated an organic light-emitting diode based on blue-fluorescent dopant 7,8,10-triphenylfluoranthene in a host of dipyrenylfluorene derivatives. The device shows pure blue emission with a peak wavelength of 456 nm and Commission International de L’Eclairage coordinate at (0.164, 0.188). An electroluminescence efficiency as high as 3.33cd∕A and external quantum efficiency of 2.48% can be achieved. Comparison of the photoluminescence and electroluminescence spectra reveals a nearly identical exciton relaxation and efficient energy transfer from the host to the dopant.