Nine kinds of poly(2,3-diphenylphenylene vinylene) (DP-PPV) derivatives, P1-P9, were synthesized via Gilch route using potassium t-butoxide (t-BuOK) as the base. Their glass transition temperatures (Tg) are in the range from 136 to 184°C. The polymers emit blue-green to yellow-green light. The photoluminescence (PL) emissions are located in the range from 496 to 550 nm. Introducing the rigid fluorenyl substituents onto DP-PPV main chains can shift the yellow-green color to pure green one. Most polymers exhibit very high electroluminescence (EL) efficiency. Two-layer light emitting device with ITO/PEDOT/polymer/Ca/Al configuration were also fabricated and characterized.