In order to gain further insight into the inter-chromophore interactions in the LHC, we turn to quantum chemical calculations. The results of the TD-DFT calculation for the isolated chromophore A1, pillar A2, and the chromophore-pillar adduct B1 are shown in Table . We note that TD-DFT calculated vertical excitation energies for BODIPY dyes are usually overestimated compared to experimental values, however the more accurate SAC-CI and CASPT2 methods are overly demanding for the size of this molecule. Conventional generalised gradient approximated (GGA) density functionals yield lower mean absolute errors for vertical excitation energies but provide incorrect natural transition orbital (NTOs), thus the 𝜔B97X-D range-separated hybrid density functional with empirical dispersion corrections was adopted.