Within this work, we have presented a detailed study of four closely related D-π-A-π-D molecules: the effective TADF chromophore Cz-AQ, its close analogue Cz-BDT, which undergoes red-shifted TADF albeit with a much lower quantum yield, and two molecules not yet synthesised Cz-BDT-SO 2 and Cz-BDF. After presenting the main structural parameters, we have presented a detailed evaluation of computational methods benchmarking five density functionals to experimental absorption data and the high-level ab initio computational reference ri-ADC(2). This highlighted that not only the energies but also the overall wavefunctions depend heavily on the functional used and particularly the amount of Hartree-Fock exchange.