Organic electrophosphorescent devices have been intensively investigated for using in full-color flat-panel display. Since the quantum efficiency of electrophosphorescent device decreases rapidly as the luminance increases, it is desirable to operate the electrophosphorescent display with active matrix rather than passive matrix. Here we report the study of driving electrophosphorescent diode with all-organic TFT. We obtained the maximum power luminance that was obtained about 90 cd/m(2). Turn-on voltage is approximately 10 V. Field effect mobility, threshold voltage, and on-off current ratio in 0.5-mum thick gate dielectric layer were 0.13 cm(2)/V s, -7 V, and 10(6) A/A. The structure of electrophosphorescent diode is ITO/TPD/BCP:Ir(PPY)(3)/BCP/Alq(3)/Li:Al/Al. In organic TFT, photoacryl is used as an insulator and pentacene as an active layer. (C) 2002 Elsevier Science B.V. All rights reserved.