Four derivatives of substituted polythiophenes (Pt) such as poly (3-dodecylthiophene) (Patl2)

poly(3

4-didodecylthiophene) (Patl212)

poly(3-octoxylthiophene) (Paot8) and poly [3-(dodecyl-co-octoxyl) thiophene](CoPt12-o8) have been synthesized using Fe(Ⅲ) as catalyst．All polymers exhibit excellent solubility in common organic solvents．Molecular weight and chemical structure of each polymer have been characterized by gel permeation chromatography (GPC) and 1H-NMR

respectively．The absorption and emission properties of polymers in chloroform solutions and spin-coating films have been studied．Except the film of Paot8

in the solution and the solid state

the polymers display different color from red to green photoluminescence. The absorption and emission maximum of Pat1212 was blue shifts more than that of Pat12 and absorption and emission maximum of Paot8 was more red shifts than that of Pat12．The band gapdata of four polymers were 2.2 eV

2.6 eV

2.1 eV and 2.1 eV

respectively

estimated from the edge of absorption spectra of spin-coating films．Single layer polymer LEDs(ITO／Polymer／Al) have been fabricated and it was found that the Pat12 emitted strong red light

the Paot8 emitted weaker red-orange light and the Pat1212 also emits weaker yellow light．The emitted wavelength was 670 nm

640 nm and 560 nm

respectively．No EL (electroluminescence) properties of CoPt12-o8 were found in our studies.