Thermally active delayed fluorescent (TADF) materials have demonstrated great potential as next-generation emitters in organic light-emitting diodes (OLEDs) due to their ability to harness 100% of the excitons to produce light without the need for noble metals as exists in phosphorescent OLEDs. TADF compounds convert non-emission triplet excitons into emissive singlets by an endothermic upconversion reverse intersystem crossing (RISC) process. The efficiency of the RISC process is governed in part by the singlet-triplet energy gap, ΔEST. A strongly twisted structure that effectively reduces the conjugation between donor and acceptor moieties is one strategy to achieve a small ΔEST as the exchange integral of the frontier molecular orbitals (FMOs) is small. However, a twisted structure exhibits significant excited-state structural relaxation, resulting in a broad emission characterized by a full width at half maximum (FWHM) larger than 70 nm. To compensate for the broad emission, filters or microcavities are required to improve color purity, but this can, unfortunately, reduce the device efficiency. Multiresonant TADF (MR-TADF) emitters have emerged as a potential solution as these rigid structures exhibit narrowband emission. First reported by Hatakeyama et al., these compounds are p-and n-doped polycyclic aromatic hydrocarbons (PAHs). By employing this approach, the singlet and triplet excited states possess an alternating pattern of increasing and decreasing electron density compared to the ground state, thus enabling a small exchange integral and consequently a small ΔEST. The rigid structure and the short range charge transfer (SRCT) nature of the excited states endow the MR-TADF compounds with bright, narrowband emission. Since the first report of MR-TADF emitters used in OLEDs in 2016 there has been intense research focused on expanding the chemical space encompassed by class of emitters. In the original works of Hatakeyama, the n-dopants were boron atoms. It is possible to replace these with carbonyl groups, and the groups of Zysman-Colman 12 Zhang, and Jiang and Liao Expanding the MR-TADF skeleton has been demonstrated to be an effective strategy to improve the performance of MR-TADF emitters, one that has been less explored in carbonyl/amine systems.