Highly Fluorescent Oligothiophenes through the Incorporation of Central Dithieno[3,2-b:2‘,3‘-d]pyrrole Units

Dithieno[3,2-b:2‘,3‘-d]pyrrole-based terthiophene (2a−c) and quaterthiophene (3a−c) analogues have been prepared from dithieno[3,2-b:2‘,3‘-d]pyrrole (1) via Stille coupling utilizing a one-pot method. In comparison to the parent oligothiophenes (T_n, where n = 2−4), the resulting dithieno[3,2-b:2‘,3‘-d]pyrrole-based systems exhibit enhanced fluorescence efficiencies in solution (up to 53%). These new oligomeric systems also allow the incorporation of solubilizing side chains without the negative steric interactions that typically reduce backbone planarity.