These structures are shown in Figure ; in all three compounds the central naphthalene is planar while the phenoxazine donor is puckered around the connecting nitrogen atom. In the related 1-PXZ-Nap and 1,4-PXZ-Nap-PXZ structures, there is a close to perpendicular dihedral angle between the phenoxazine and naphthalene groups of 82.3° and 82.0°, respectively, while the less sterically hindered 2-PXZ-Nap has a more relaxed dihedral angle of 72.0°. The difference in geometry between the 1-PXZ-Nap/1,4-PXZ-Nap-PXZ and 2-PXZ-Nap agrees with the trend predicted by DFT (Table ). A complete analysis of the obtained crystal structures is available in the Supporting Information Compared to the naphthalene-based emitters that have been previously reported, 9,10 the HOMO energies of these three emitters are generally more destabilised while the LUMO energies are notably more stabilised. As such, the HOMO-LUMO gaps are smaller at ca. 1.6 eV, compared to ca. 3.0, 3.0 and 2.7 eV for 1,4-naphthyl-CF3, 1,5-naphthyl-CF3, and DPTZN, 10 respectively (Table ).