A series of new poly(p-phenylene vinylene) derivatives with different dendritic pendants-poly{2-[3',5'-bis(2"-ethylhexyloxy)benzyloxy]-1,4-phenyleneviny lene} (BE-PPV), poly {2-[3', 5'-bis(3", 7"-dimethyl)octyloxy]-1,4-phenylenevinylene} (BD-PPV), poly(2-{3',5'-bis[3",5"-bis(2"'-ethylhexyloxy)benzyloxy]benzyloxy}-1,4-p henylenevinylene) (BBE-PPV), poly(2-13',5'-bis[3",5"-bis(3"',7"'-dimethyloctyloxy)benzyloxylbenzyloxy l1,4-phenylenevinylene) (BBD-PPV), and poly[(2-[3',5'-bis[3",5"-bis(2"'-ethylhexyloxy)-benzyloxy]benzyloxy}-1,4 -phenylenevinylene)-co-(2-{3',5'-bis[3",5"-bis(3"',7"'-dimethyl-octyloxy)benzyloxy]benzyloxy}-1,4-phenylenevinylene)] (BBE-co-BBD-PPV; 1:1) -were successfully synthesized according to the Gilch route. The structures and properties of the monomers and the resulting conjugated polymers were characterized with H-1 and C-13 NMR, elemental analysis, gel permeation chromatography, thermogravimetric analysis, ultraviolet-visible absorption spectroscopy, photoluminescence, and electroluminescence spectroscopy. The obtained polymers possessed excellent solubility in common solvents and good thermal stability, with a 5% weight loss temperature of more than 328 degrees C. The weight-average molecular weights and polydispersity indices of BE-PPV, BD-PPV, BBE-PPV, BBD-PPV, and BBE-co-BBD-PPV (1:1) were in the range of 1.33-2.28 x 10(5) and 1.35-1.53, respectively. Double-layer light-emitting diodes (LEDs) with the configuration of indium tin oxide/polymer/tris(8-hydroxyquinoline) aluminum/Mg:Ag/Ag devices were fabricated, and they emitted green-yellow light. The turn-on voltages of BE-PPV, BD-PPV, BBE-PPV, BBD-PPV, and BBE-co-BBD-PPV (1:1) were approximately 5.6, 5.9, 5.5, 5.2, and 4.8 V, respectively. The LED devices of BE-PPV and BD-PPV possessed the highest electroluminescent performance; they exhibited maximum luminance with about 860 cd/m(2) at 12.8 V and 651 ed/m(2) at 13 V, respectively. The maximum luminescence efficiency of BE-PPV and BD-PPV was in the range of 0.37-0.40 cd/A. (c) 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3126-3140, 2005.