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The pursuit of highly efficient thermally activated delayed fluorescence (TADF) emitters with two‐photon absorption (2PA) character is hampered by the concurrent achievement of a small singlet‐triplet energy gap (ΔEST) and high photoluminescence quantum yield (ΦPL). Here, by introducing a terephthalonitrile unit into a sterically crowded donor‐π‐donor structure, inducing a hybrid electronic excitation character, we designed unique TADF emitters possessing 2PA ability. This rational molecular design was achieved through a main π‐conjugated donor‐acceptor‐donor backbone in line with locally excited feature renders a large oscillator strength and transition dipole moment, maintaining a high 2PA cross‐section value. The ancillary N‐donor‐acceptor‐donor with charge transfer character highly balances the TADF phenomenon by minimizing ΔEST. A near‐unity ΦPL value with a large radiative decay rate over an order of magnitude higher than the intersystem crossing rate and a high horizontal orientation ratio of 0.95 were simultaneously attained for TPCz2NP. The organic light‐emitting diodes fabricated with this material exhibit a high maximum external quantum efficiency of 25.4 % with an elevated 2PA cross‐section (σ2) value up to 143 GM at 850 nm. These findings offer a venue for designing high‐performance TADF emitters with exceptional performance inclusive of 2PA properties, expanding for future functional material design. [ABSTRACT FROM AUTHOR]

Host–guest assemblies of a designed 1,4-bis(diarylamino)naphthalene and V-shaped aromatic amphiphiles consisting of two pentamethylbenzene moieties bridged by an m -phenylene unit bearing two hydrophilic side chains emerged as highly reducing photoredox catalysis systems in water. An efficient demethoxylative hydrogen transfer of Weinreb amides has been developed. The present supramolecular strategy permits facile tuning of visible-light photoredox catalysis in water. [ABSTRACT FROM AUTHOR]

Two novel deep-blue multi-resonance thermally activated delayed fluorescence (MR-TADF) emitters, 1B-CzCrs and 2B-CzCrs, containing a fused carbazole unit were synthesized. The carbazole contributed to the emergence of TADF in these small molecules. Particularly, organic light-emitting diodes with 1B-CzCrs doped in the mCP host achieve a maximum external quantum efficiency of 12.8% at CIE coordinates of (0.146, 0.062).

A caged carboxylic acid with a novel two-photon (TP)-responsive donor-π-donor coumarin backbone with a quadrupolar nature was designed and synthesized in this study. The newly synthesized coumarin derivative showed a strong one-photon (OP) absorption band (ε ≈ 29000 cm -1 M -1 ) in the visible region (>∼400 nm). Time-dependent density functional theory calculations predicted a sizable TP absorption cross-section with a maximum at ∼650 nm significantly lager than that related to the OP absorption band. This is confirmed experimentally using TP excited fluorescence in the fs regime that leads to TP absorption cross-section of 18 and 5.6 GM at 680 and 760 nm, respectively. The OP photolysis (400 nm) and near-infrared-TP photolysis (750 nm) of the caged benzoic acid resulted in a clean formation of benzoic acid and an aldehyde.