We have synthesized a thermally stable and high molecular weight fluorescent poly(phenylenevinylene) (PPV) incorporating side-chain-tethered dendritic phenyl groups (DENPPV) through Gilch route; this DENPPV has a low abundance of tolane-bisbenzyl defects. Intramolecular energy transfer from the dendritic phenyl side group to the PPV backbone was evidenced from UV-vis and photoluminescence spectra of the DENPPV polymer and its model compound. Copolymers of DENPPV with 2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene (MEHPPV) display excellent photoluminescence both in solution and in the solid state; the highest quantum yield we observed was 82%. The electroluminescence of the copolymer MEHPPV/DENPPV (molar ratio: 25/75) was 70% higher than that of MEHPPV (0.12 lm/W vs 0.07).