In 2016, Hatakeyama et al. reported a new class of TADF compounds, known as multiresonant TADF (MR-TADF) emitters. In these compounds, election-donating and electron-accepting atoms are embedded within a polycyclic aromatic framework. The complementary mesomeric effects of these atoms produces an alternating pattern of increasing and decreasing electron density in the excited states compared to the ground state, resulting in a modest DEST. The short-range charge transfer (SRCT) character of the emissive S1 state and the rigid structure results in small Stokes shifts, narrowband emission, and high photoluminescence quantum yields (FPL). MR-TADF emitters can basically be divided into two categories based on the nature of the acceptor: boronbased emitters and carbonyl-based emitters. The first carbonyl-based MR-TADF emitter (DiKTa, aka QAO, QAD) was reported by both us and Jiang, Liao and coworkers. It emits at λPL of 466 nm with a full width at half maximum (FWHM) of 32 nm and has a ΔEST of 0.18 eV in toluene. As 5 wt% doped film in mCP, this compound has a FPL of 72.4% and a delayed lifetime τd of 93 μs. Depending on the device configuration, the OLEDs showed a maximum external quantum efficiency (EQEmax) of 19.4% at lEL of 468 nm or an EQEmax of 14.7% at lEL of 465 nm. Since these initial reports, many DiKTa-based MR-TADF emitters have been reported. The structures and properties are summarized in the ESI (Figures S22-S24, Table ). Of particular relevance, Chen et al. reported a derivative of DiKTa, MTDMQAO, containing a 2,4-dimethyl-1,3,5-triazine acceptor. MTDMQAO exhibits narrowband blue emission at λPL of 455 nm (FWHM of 19 nm) and has a ΔEST of 0.20 eV in toluene. The FPL is near unity at 99% and the τd is 32 μs in the 10 wt% doped film in mCP. The OLEDs with MTDMQAO showed high EQEmax of 29.4% at λEL of 472 nm. We reported the emitter 3TPA-DiKTa, which contains three triphenylamine donors about the central DiKTa core. In 2 wt% doped films in mCP, 3TPA-DiKTa emits at λPL of 551 nm (FWHM of 58 nm), has a ΔEST of 0.13 eV and a τd of 131μs. The devices achieved very high EQEmax of 30.8% at 552 nm (FWHM of 62 nm).