A new strategy for the efficient synthesis of thieno[3,2-b]benzofuran derivatives (15 examples) was achieved on the basis of successive regioselective intermolecular Suzuki and newly developed intramolecular Ullmann C-O reactions in up to a 70% overall yield. The fast intramolecular C-O reaction can be realized by an efficient catalytic combination of CuI/1,10-phenanthroline in up to a 97% yield. This method is suitable for the construction of highly fused thieno[3,2-b]furan-containing heterocycles including DTBDF and TTDBF. The π-π and hydrogen-bonding interactions observed for the C-DTBDF single crystal suggest its great potential for OFET applications in the near future.

To meet the imminent requirement of fullerene‐free electron acceptors, a new ladder‐type heteroarene benzodi(thienopyran) (BDTP) is designed and synthesized by embedding pyran rings in [2,2‐(2,5‐dialkyloxy‐1,4‐phenylene)dithiophene] (PDT) for organic photovoltaic (OPV) applications. Originating from the strong p–π conjugation of the oxygen atom in the pyran rings, electron‐rich BDTP results in the BDTP‐cored molecular acceptor, NBDTP, with strong intramolecular charge transfer effect. With sp3 carbons in pyran rings, NBDTP have the flexibility of targeted modification to resolve the solubility as well as the morphological tuning by handy alkyl chain attachment. As a result, the fusion of pyran rings in BDTP means that the acceptor exhibits a narrow optical band gap of 1.58 eV and a high LUMO energy level of −3.79 eV. Meanwhile, blend morphology of NBDTP‐based OPVs shows fine tunability via thermal annealing. Owing to the beneficial optical absorption, suitable energy‐level alignment, favorable molecule packing, and proper morphology, the optimized NBDTP‐based OPVs achieve a power conversion efficiency of up to 10.1%, which exemplifies the potential of utilizing molecular acceptors featuring ladder‐type heteroarenes for high‐performance OPVs.

We report herein a synthesis of benzofuro[3,2‐b]benzofuran (BFBF) by an intramolecular Ullmann C−O coupling reaction. To tune the film forming ability and self‐assembling behaviour, the derivative possessing two alkyl chains, 2,7‐dioctylbenzofuro[3,2‐b]benzofuran (C8‐BFBF), was further prepared. The packing structures of these two compounds were studied by XRD analysis, showing a two‐dimensional (2D) stacking structure in the solid state. DFT calculations indicated that C8‐BFBF exhibited large transfer integrals along the two stacking directions. The OFET devices based on C8‐BFBF showed typical hole transport properties with mobility up to 0.076 cm2 V−1 s−1.

Two new selenophene‐flanked DPP based conjugated polymers were developed. Incorporating half‐fused selenophene‐flanked DPP into the polymer is proven to efficiently improve the ambipolar mobilities and balance the hole/electron mobility ratio.