Thiophenes and Their Benzo Derivatives: Structure

This article details recent advances in the structural and spectroscopic investigation of thiophene molecules and their benzo-derivatives. These species are gaining a large interest for multiple applications as organic semiconductors. Key concepts accompanying the whole discussion are those related to the double aromatic/biradicaloid and quinoidal characters that characterize these molecular materials, which have important consequences on their optoelectronic properties and thus need to be known and possibly predicted. Relevance is also given to the description of cases featuring different aggregation phenomena at the solid state, which is also central for charge transport and light emission properties.