Electronic property and reactivity of novel fused thiophene

A novel fused thiophene (3,4-dihydro-2H-thieno[3,4-b]pyran) was prepared via intramolecular transetherification. The corresponding polythiophene was obtained by chemical oxidative polymerization and it was soluble in CHCl3. In UV–vis absorption analysis at various applied potentials, the polythiophene exhibited a distinct electrochromic behavior. Electrochemical polymerization of the monomer was successfully carried out in a viscous ionic liquid, while it was failed in organic solvent systems.