Four molecule design strategies of n-type conjugated polymers for organic thin-film transistors are summarized and discussed.

A series of 1,3‐indandione‐terminated π‐conjugated quinoids were synthesized by alkoxide‐mediated rearrangement reaction of the respective alkene precursors, followed by air oxidation. This new protocol allows access to quinoidal compounds with variable termini and cores. The resulting quinoids all show LUMO levels below −4.0 eV and molar extinction coefficients above 105 L mol−1 cm−1. The optoelectronic properties of these compounds can be regulated by tuning the central cores as well as the aryl termini ascribed to the delocalized frontier molecular orbitals over the entire molecular skeleton involving aryl termini. n‐Channel organic thin‐film transistors with electron mobility of up to 0.38 cm2 V−1 s−1 were fabricated, showing the potential of this new class of quinoids as organic semiconductors.

Conjugated polymers (CPs) with deep LUMO energy levels (E LUMO s) are essential for developing n-type organic electronics. However, few approaches can markedly lower the E LUMO s of CPs. Herein, this issue is addressed by the introduction of a quinoidal building block into the polymer chain. Two CPs, PIQ-A and PIQ-O, are synthesized based on an indandioneterminated quinoidal unit, with alkyl or oligo(ethylene glycol) side chains on the comonomer, respectively. The CPs show ultralow E LUMO s of ca. −4.30 eV, which is lower by 0.75 eV compared to the analogous polymer with aromatic conjugated structure. The deep LUMO energy levels endow the CPs with unipolar n-type transport behavior in organic thin-film transistors and efficient n-type doping in organic thermoelectrics, with doped PIQ-O showing an optimized electrical conductivity of 0.43 S cm −1 and a power factor of 4.24 μW m −1 K −2 . Importantly, the electrical conductivity of doped polymer thin films (∼50 nm) barely changes after a 7 day exposure to air, and the doped PIQ-O film shows an electrical conductivity of 0.39 S cm −1 even after a 15 day exposure to air. This work provides a new approach to develop CPs with ultralow LUMO energy levels, toward high-performance and potentially airstable n-type organic electronics.

A novel unsymmetrical fiveand six-membered sulfur-annulated heterocyclic perylene diimides (PDI) derivative was obtained by a one-pot and catalyst-free synthesis in a high yield. The unsymmetrical PDI exhibits a noteworthy bathochromic shift absorption of up to 700 nm and a lowlying lowest unoccupied molecular orbital level of −3.99 eV. The compound owns a complete planar structure and a high electron mobility of 4.8 × 10 −3 cm 2 V −1 s −1 in solutionprocessable top-gate/bottom-contact organic field-effect transistor device.

A highly efficient approach to C­(sp3)–C­(sp3) bond construction via on-DNA photoredox catalysis between on-DNA alkenes and N-aryl tertiary amines was developed. The methodology demonstrated 55%–95% conversions without obvious DNA damage, as seen by qPCR tests. Furthermore, various functional groups, such as carboxylic acids, aldehydes, and aryl halides, that can be used to create library diversities were shown to be tolerant of the C–H activation conditions.