White polymeric light-emitting diodes (WPLEDs) from a single polymer system were developed by incorporating 2,3-bis(4-methyloxyphenyl)quinoxaline and 5,8-bis(N,N-diphenylamino)-2.3-bis(4-methyloxyphenyl)quinoxaline into poly(9,9-dioctylfluorene). All copolymers showed good thermal stability with 5% weight loss temperatures above 420 degrees C, and glass transition temperatures ranged from 86 to 143 degrees C. Electroluminescence (EL) devices with indium tin oxide/poly(3,4-ethylenedioxythiophene):poly-(styrenesulfonic acid)/emission layer/Ca/Ag were found to emit white hat with Commission Internationale de l'Eclairage (CIE) coordinates of (0.33, 0.40) and (0.30, 0.36). These devices exhibit a highest brightness of 12 300 cd/m(2) and a maximum current efficiency of 2.56 cd/A.