A reasonable shortcut to predicting photo-optical molecular properties is to approximate electronic excitation energies with energy differences between molecular orbital (MO) energy levels . Of particular interest here is the energy difference between the highest occupied MO (HOMO) and the lowest unoccupied MO (LUMO). This so-called "HOMO-LUMO" gap often correlates very well with the lowest-energy, and hence most accessible, excited state that a molecule typically adopts upon energy intake due to the absorption of photons. Thus, HOMO-LUMO gaps have recently become the target of AI-based approached to photoactive molecules . However, as mentioned above, this approach is only a reasonable shortcut, since for the inverse design of molecular structures with desirable photo-optical properties the entire absorption and/or emission spectrum over the energy range of visible light is required . Ab initio multireference wavefunction electronic structure methods such as CAS-PT2 and NEVPT2 are able to cover these energy ranges and provide a measure for absorption/emission intensity via the prediction of oscillator strengths, and therefore accurately predict molecular dye candidate photophysical properties. However, this capability comes with a substantial price: The calculation of an UV/Vis absorption spectrum for molecules containing only tens of atoms are impractical on standard laptop or even Linux-operated workstations, due to the enormous required computational effort and resources in CPU power and memory. Computationally less demanding methods are density functional theory (DFT)-based excited states time-dependent (TD)-DFT methods , with the approximate TD-density-functional tight-binding (TD-DFTB) method being one of the computationally most economical methods .