Phosphole–Thiophene Hybrid: A Dual Role of Dithieno[3,4-b:3′,4′-d]phosphole as Electron Acceptor and Electron Donor

We have synthesized dithieno[3,4-b:3′,4′-d]phosphole derivatives as a new type of thiophene-fused phospholes. These dithienophospholes were found to show intramolecular charge transfer interactions by introducing electron-donating or -withdrawing groups on the peripheral aryl groups. Namely, they exhibit the unique hybrid character of electron-withdrawing phosphole and electron-donating thiophene.