we assign the lowest triplet state to be of mixed CT/LE character. As the phosphorescence spectra for the three compounds possess the same shape and energy, this reveals that each of the donor-acceptor units is not strongly coupled to one another. This conclusion is also supported by the analysis of their absorption spectra, where no new features appear along the series. The phosphorescence spectra occur at 0.17-0.19 eV lower in energy compared to their corresponding prompt fluorescence (Table ), providing near identical DEST gaps. Compared to the reference DCzBN1 (ΔEST = 0.31 eV in toluene), the ΔEST values for 4TABN1, 5TABN2 and 6TABN3 in toluene are much smaller, which should translate into compounds showing more pronounced TADF. For reference, a version of Figure with an energy scale as the leading axis is shown in the ESI as Figure .