To gain deeper insight into the electronic structures of these arylated pentalenides and understand the polarisation effects introduced by the various substituents, we carried out DFT calculations on derivatives 2, 3, 9, 10, and 12 in comparison with the parent pentalenide 1. To better align the calculated geometries with the solid-state molecular structures from X-ray crystallography, and to obtain meaningful frontier orbital energies, we included two Li + counterions in trans η 5 position as found in the solid state. For aromaticity and charge distribution calculations we used the bare dianions as a more realistic model for the speciation in solution where solvent-separated ion pairs exist (see above). Additionally, this avoids possible distortions of charge localisation due to coulomb attraction.