A Tricyclic Framework with Integrated B←N and Cyano Dual Functionalization for Superior n-Type Organic Electronics

n-Type conjugated polymers featuring low-lying lowest unoccupied molecular orbital (LUMO) energy levels are essential for achieving high-performance n-type organic thin-film transistors (OTFTs) and organic thermoelectrics (OTEs). However, the synthesis of acceptors with strong electron-withdrawing characteristics presents a significant challenge. Herein, a peripheral functionalization strategy is employed on the tricyclic framework anthracene by introducing dual N,O-bidentate BF₂/B(CN)₂ groups to enhance its electron-withdrawing capability. This approach successfully navigates synthetic challenges, leading to the development of two novel acceptor building blocks: DBNF and DBNCN. Compared to the counterparts with a single N,O-bidentate BF₂/B(CN)₂ moiety, DBNF and DBNCN exhibit an extended π-backbone, enhanced molecular packing, and improved electron-withdrawing properties. Utilizing these innovative acceptor monomers, copolymers, PDBNF and PDBNCN, are synthesized, which exhibit considerably suppressed LUMO ≈-4.0 eV. The deep LUMO of PDBNF together with its favourable bimodal packing orientation leads to remarkable electron mobility of 3.04 cm² V^-1 s^-1 with improved stability in OTFTs. Importantly, efficient n-doping in OTEs is achieved with PDBNCN, exhibiting exceptional conductivity of 95.5 S cm^-1 and a maximum power factor of 147.8 μW m^-1 K^-2-among the highest reported for solution-processed n-type polymers. This work underscores the effectiveness of introducing dual B←N and cyano functionalities in attaining high-performance n-type plastic electronics.