The dihedral angles between the bridging phenylene rings and the peripheral phenyl rings of the triphenyl amine in 3TPA-DiKTa range between 11.35 and 32.00°. Due to the presence of the phenylene bridge in 3TPA-DiKTa, the distance between DiKTa nitrogen atom and diphenylamine nitrogen atom is 9.9 Å, larger than for 3DPA-DiKTa (5.5 Å). The degree of planarity of the geometries of both molecules was then calculated by PBE0/6-31G(d,p) based on the crystal structures. Overall, both molecules show planarity ratios of 67% for 3TPA-DiKTa 68% for 3DPA-DiKTa (Figure ), indicating that the compounds in the crystal structure geometry are reasonably planar.