Optically active regioregular polythiophenes

3-Alkyl substituted polythiophenes have been studied in detail with respect to their optoelectronic properties as well as their solvatochromic and thermochromic behavior. It is now well-accepted, that two distinct forms can be present: a predominantly coplanar structure (in an aggregated form) in a poor solvent and a conformationally disordered non-planar structure in good solvent. We investigated several regioregular optically active polythiophenes and found that significant induced optical activity in the p-p*-transition of substituted polythiophenes can be obtained, provided the chiral substituents are positioned in a well-defined fashion. Due to the presence of only one enantiomeric form in the side chain there is a preference for the backbone to form one chiral structure over the other in the aggregated state. [on SciFinder (R)]