A series of cyclopentadithiophene based polymers have been synthesized by oxidative polymn. or palladium-catalyzed coupling reactions. Polymers have been prepd. with backbones contg. benzothiadiazole, benzoxadiazole, 2,2'-bithiophene, Ph and fluorene units. The backbone structure is shown to have a large effect on the film morphol., and the optical and electrochem. properties in soln. and the solid state. We show that the polymer compn. can be used to tune the band gap over the entire visible spectrum. Spin-coated films of these polymers have been used as the active layer of org. field effect transistors and hole mobilities up to 3.7 * 10-3 cm2 V-1 s-1 have been measured under ambient conditions. [on SciFinder (R)] ; CAN 153:62648 35-5 Chemistry of Synthetic High Polymers Organic Materials Innovation Centre, School of Chemistry,The University of Manchester,Manchester,UK. Journal 1228684-77-2P; 1228684-79-4P; 1228684-80-7P; 1228684-82-9P; 1228684-84-1P; 1228684-87-4P; 1228684-89-6P; 1228684-91-0P Role: PRP (Properties), SPN (Synthetic preparation), PREP (Preparation) (cyclopentadithiophene based polymers for comparison of optical, electrochem. and org. field-effect transistor characteristics); 6165-68-0 (Thiophene 2-boronic acid); 54286-63-4; 73183-34-3; 365547-21-3 Role: RCT (Reactant), RACT (Reactant or reagent) (cyclopentadithiophene based polymers for comparison of optical, electrochem. and org. field-effect transistor characteristics); 1228684-78-3P; 1228684-81-8P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (monomer; cyclopentadithiophene based polymers for comparison of optical, electrochem. and org. field-effect transistor characteristics)