摘要： Organic entities that can transport electrons are seldom available to develop adequate bipolar host materials applicable for solution-processable thermally activated delayed ?uorescence (TADF)-organic light-emitting diodes (OLEDs). Therefore, the introduction of new electron-af?ne entities that plausibly demonstrate high triplet energy (ET) is of urgent need. In this contribution, we introduced benzimidazo[1,2-a][3,1]benzothiazine (BBIT) as a novel electron-af?ne entity and developed two new bipolar host materials, CzBBIT and 2CzBBIT. Both host materials exhibit high ET of 3.0 eV, superior thermal robustness with the thermal decomposition temperature of up to 392?C, a glass transition temperature of up to 161?C, and high solubility in common organic solvents. Consequently, the solution-processable OLEDs fabricated using a recognized IAcTr-out as the green TADF emitter doped into CzBBIT as the host, realized a maximum external quantum ef?ciency (EQE) of 23.3%, while the 2CzBBIT:IAcTr-out blend ?lm-based device displayed an EQE of 18.7%. These outcomes corroborated that this work could shed light on the scienti?c community on the design of new electron-af?ne entities to establish the effective use of bipolar host materials toward pro?cient solution-processable TADF-OLEDs.