The longest quinoidal oligothiophene: a Raman story

The main research on the family of aromatic and quinoidal oligothiophenes is described, with a focus on their longest members. We have described how the comprehensive understanding of the vibrational Raman spectra of oligothiophenes in a variety of situations permitted the elucidation of properties of fundamental importance, not only for basic research in molecular physics and in physical chemistry, but also for applications. We have written the Raman story that brought us to the elucidation of the biradicaloid nature of the longest quinoidal oligothiophene.