To date, excellent progress has been made in terms of the design of efficient TADF emitters and OLEDs across the visible spectrum. Owing to the energy gap law, the design of efficient deep red (DR) or near-infrared (NIR) TADF emitters remains challenging and there are far fewer examples of these compared to blue and green congeners . DR and NIR emitters are integral components in medical diagnostics and biomedical imaging , optical communication , remote sensing , security , night vision , and data storage . Anthraquinone is a strong acceptor and has been incorporated in a number of low-energy emissive donor-acceptor TADF emitters. In early work, Adachi and co-workers reported a family of emitters containing an anthraquinone acceptor linked to diphenylamine (a1-a3) or triphenylamine donors (b1-b3). The family of compounds b1-b3 have higher ΦPL, ranging from 59-62%, compared to a1-a3 (ΦPL = 10-20%) in toluene. Despite their similar FPL and ∆EST [∆EST for b1-b4 24 eV) is nearly maintained with that of a1-a3 (0.17-0.29 eV)], the delayed lifetime (τd) values of the former series span a wide range from 17-416 µs; the td of the latter series range from 62 µs-4.6 ms. Compounds b1-b4 emit with lPL ranging from 557-609 nm while a1-a4 emit with lPL ranging from 601-662 nm in toluene. Among b1-b4, the device with compound b1 showed the best performance, with a maximum external quantum efficiency, EQEmax, of 12.5% at λEL of 624 nm (Figure ). reported two near-infrared anthraquinone dendrimers MPPA-Cz and MPPA-3Cz that both emit at 667 nm, have ΦPL of 6 and 8%, and ∆EST of 0.17 and 0.16 eV in toluene, respectively, while their delayed lifetime (τd) are 0.36 and 0.93 µs in neat film. The solution-processed non-doped OLEDs with MPPA-Cz and MPPA-3Cz showed very low EQEmax of 0.06 and 0.25% at λEL of 728 and 715 nm, respectively (Figure ). Previously, studied D-A-D systems where the two donors are attached to the anthraquinone acceptor at the 2and 6-positions while Bin et al. reported D-A systems consisting of a carbazole or triphenylamine donor bound to the anthraquinone acceptor at the 2-position. Compounds Cz-AQ and TPA-AQ have ΦPL of 28 and 52%, ∆EST of 0.11 and 0.05 eV neat film, respectively. The solution-processed non-doped OLEDs showed EQEmax of 5.8 and 7.5% at λEL of 572 and 612 nm (Figure ). studied the properties of b1 and its 1,8-disubstituted analog (1,8-2TPA-AQ) in terms of their chemical structure by single crystal X-ray diffraction and their optoelectronic properties evaluated computationally at the B3LYP/6-31G(d) level; similarly, the author contrasted TPA-AQ (TPA substituted at the 2-position of AQ) and its 1-substituted analogue (1-TPA-AQ). The calculations revealed that 1-TPA-AQ and 1,8-2TPA-AQ both have smaller ∆EST of 0.08 eV and have low oscillator strength (f = S1→S0) of 0.023 and 0.017 compared to TPA-AQ (∆EST = 0.19 eV, f = 0.141, S2→S0) and b1 (∆EST = 0.21 eV, f = 0.33, S2→S0). Thus, there seems to be a trade-off between TADF efficiency and ΦPL depending on the substitution pattern of the donors about the anthraquinone. reported the compound AQ-PhDMAC that contains a "crooked" conformation of DMAC donor due to the introduction of a phenyl group at the α-position to the nitrogen of the DMAC donor (PhDMAC = 9,9-dimethyl-4-phenyl-9,10-dihydroacridine). Control emitter AQ-DMAC that does not contain the α-phenyl group was also investigated for the comparison. AQ-PhDMAC and AQ-DMAC emit at 586 nm and 610 nm in toluene, respectively. AQ-PhDMAC has a higher ΦPL of 89% than AQ-DMAC (ΦPL of 63%) in 5 wt% doped films in CBP but has a much larger ∆EST of 0.22 eV and longer τd of 63.6 µs than the control emitter (∆EST = 0.002 eV, τd = 21.2 µs), which is due to the more planar conformation adopted by AQ-PhDMAC (torsion angle of 20° between the PhDMAC and phenylene bridge) while the torsion angle between the DMAC and the phenylene bridge increased to 80° in AQ-DMAC. Despite the more inefficient TADF, the orange-red OLEDs with AQ-PhDMAC showed higher EQEmax of 18.1% at λEL of 580 nm than the devices with AQ-DMAC (EQEmax = 13.9% at λEL = 580 nm) in 5 and 3 wt% doped CBP host, respectively (Figure ).