Multi-resonant TADF (MR-TADF) materials based on heteroatom-doped polycyclic aromatic frameworks have garnered significant attention in recent years as they show bright, narrowband emission. The TADF behavior emanates from an electron density distribution of the frontier molecular orbitals (FMOs) that shows an alternating pattern of density on adjacent atoms/groups resulting in the small singlet-triplet energy gap (ΔEST). The rigid aromatic framework of these compounds effectively suppresses vibrations and structural relaxation, favoring narrowband emissions and high ΦPL. The high colour purity and high ΦPL of MR-TADF emitters also make them promising probes for bioimaging that should show high signal-to-noise ratios. This is particularly significant for red MR-TADF materials, as red light can penetrate tissue more deeply within the biological transparency window (600-1350 nm). Although donor-acceptor TADF materials have shown attractive potential as bioimaging reagents as discussed above, to the best of our knowledge there are no reported examples of MR-TADF emitters being used as bioimaging probes or formulated as g-Odots. Herein, two orange-to-red MR-TADF molecules based on a donor-decorated DiKTa design were developed (Figure ). PhDPA-DiKTa and MeODPA-DiKTa show orange and red moderately broad emission in toluene, respectively, with lPL of 592 nm (FWHM = 45 nm) to 633 nm (FWHM = 72 nm), where the emission is tuned as a function of the electron-donating strength of the substituents. As 5 wt% doped films in mCP, PhDPA-DiKTa emits at lPL of 617 nm (FWHM = 57 nm) and has a FPL of 69%, while MeODPA-DiKTa emits at lPL of 655 nm (FWHM = 71 nm) and its FPL is lower at 27%. The DEST of these films of PhDPA-DiKTa and MeODPA-DiKTa are 0.16 and 0.12 eV, respectively, and their average delayed lifetimes, td, are 658.4 to 249.2 µs, respectively. G-Odots based on PhDPA-DiKTa and MeODPA-DiKTa were prepared by encapsulating these emitters and mCP into an amphiphilic DSPE-PEG2k polymer for use as bioimaging reagents. Although the emission spectra of both g-Odots are slightly broader compared to those of the 5 wt% doped films in mCP, they showed a deeper red emission (lPL = 618 nm, FWHM = 65 nm for PhDPA-DiKTa g-Odots; lPL = 663 nm, FWHM = 78 nm for MeODPA-DiKTa g-Odots). Furthermore, both g-Odots conserved their TADF properties, with td of 203.9 µs for PhDPA-DiKTa and 131.6 µs for MeODPA-DiKTa. These g-Odots were used as biological imaging probes in HeLa cells via single-photon microscopy measurements.