Conjugated organic polymers like polythiophenes have attracted a lot of interest during the last decade. They show interesting properties in their reduced and oxidized (doped) forms, e.g high electrical conductivity. These properties are dependent on the conjugation of the π-system. Oligothiophenes are accepted as model compounds for the conducting polymers. A detailed investigation of the conformation and charge distribution of oligothiophenes was conducted. But are there hints of an vertical interaction between the chains of the polythiophenes?Semiempirical calculations (AM1, MNDO und PM31) were used to calculate the conformational hypersurfaces of the radical anion/kation, of the neutral molecule and of stacks shown in Figure 2.