In the case of TBAP the IP and EA values were also calculated using an alternative strategy, starting from the crystal structure. Here we first the experimental crystal structure of TBAP is energy minimized in a periodic DFT calculation using the B97-3c approach as implemented in Crystal17. Subsequently, three cluster models were cut out of the DFT optimized crystal structure, corresponding to one monomer, one monomer (1C) with a molecule above and below it, as well as the phenyl groups of the laterally adjacent molecules (1C+, see Fig. ), and an analogous structure with a tetramer in the centre (4C+). The IP and EA values of the three cluster models were calculated in the same way as for the isolated molecules discussed above, other than that in the last two cases we used the ONIOM QM/MM approach and described the molecule (fragments) around the monomer and tetramer using the UFF forcefield.