A concept of single-molecular light emission is theoretically proposed by using a pi-conjugated molecule linked by meta-phenylene couplers, gold as the anode, and calcium as the cathode. The molecule, which comprises perylene at the center as the light-emitting moiety and two phenylacetylenes as the hole- and electron-transporting moieties, is designed to have localized pi-MOs with an appropriate energy gradient to efficiently transport carriers at the single-molecular level. (C) 2004 Elsevier B.V. All rights reserved.