For step (i) the molecular geometries of Cz-BDT and Cz-AQ were optimised at the ωB97X-V/def2-SVP level of theory and confirmed as being minimum energy structures by a vibrational analysis at the same level. For step (ii), to determine an appropriate computational method to describe the excited state character of the molecules, the first 10 vertical excitations are first computed at the ri-ADC(2) level, using the def2-TZVP basis set. The first 10 excited states are, then, recomputed using five different density functionals with TD-DFT in the Tamm-Dancoff approximation (TDA), considering that the TDA is expected to reduce problems associated with triplet instabilities. The density functionals evaluated are PBE, 65 PBE0, 66 ωPBEh, CAM-B3LYP, and ωB97X-V, with the def2-SV(P) basis set. In the case of ωPBEh, we used a range separation parameter of ω = 0.1 a.u. and a global amount of Hartree-Fock exchange of 20% following previous experience on related donor/acceptor systems. The ωPBEh/def2-SV(P) level of theory is selected for step (iii)