Poly [2-methoxy-5-(2'-ethylhexyloxy)-p-phenylenevinylene] (MEH-PPV) with a molar mass of 26-47 x 10(4) g mol(-1) and a polydispersity of 2.5-3.2 was synthesized by a liquid-solid two-phase reaction. The liquid phase was tetrahydrofuran (THF) containing 1,4-bis(chloromethyl)-2-methoxy-5-(2'-ethylhexyloxy)benzene as the monomer and a certain amount of tetrabutylammonium bromide as a phase-transfer catalyst. The solid phase consisted of potassium hydroxide particles with diameters smaller than 0.5 mm. The reaction was carried out at a low temperature of 0 degreesC and under nitrogen protection. No gelation was observed during the polymerization process, and the polymer was soluble in the usual organic solvents, such as chloroform, toluene, THF, and xylene. A polymer light-emitting diode was fabricated with MEH-PPV as an active luminescent layer. The device had an indium tin oxide/poly(3,4-ethylenedioxyl-thiophene) (PEDOT)/MEH-PPV/Ba/Al configuration. It showed a turn-on voltage of 3.3 V, a luminescence intensity at 6.1 V of 550 cd/m(2), a luminescence efficiency of 0.43 cd/A, and a quantum efficiency of 0.57%. (C) 2004 Wiley Periodicals, Inc.