To better understand the lowered absorbance upon attaching the chromophore and pillar to the LHC centre, the UV absorption behaviour of these components was probed using computational chemistry methods. Unless otherwise stated, all calculations were carried out using Q-Chem 5.2. The geometry of isolated fragment molecules (chromophore, pillar, chromophore + pillar) as shown in Table were first optimised using the 𝜔B97X-D functional with the cc-pVDZ basis set. The effect of the solvent environment was included using the conductor-like polarisation continuum model (CPCM) with dielectric constant parameter for dichloromethane, 𝜀 = 8.93. A total of 30 vertical singlet-singlet excitation energies were determined using time-dependent density functional theory (TD-DFT) with the 𝜔B97X-D functional and the aug-cc-pVDZ basis set, and the corresponding natural transition orbitals (NTOs) were plotted to provide a chemically intuitive picture of the electronic excitation. 17