In this section, we used a dataset previously generated by some of us using rational design rules, comprising 16 different molecular scaffolds, the details of which will be presented elsewhere. Out of 68695 compounds, only 5 cyclobutadienes failed to compute as they had rearranged in the DFT simulations and our topology detection algorithm interpreted them as having formed transannular single bond. This corresponds to a success rate of 99.99%. To put this into context, ~25% of the CASSCF calculations and 9% of the CIS calculations failed in a recent HTVS workflow by Troisi, Padula and co-workers. The total runtime using four cores on the M2 processor was 1.82 CPU hours, with a mean time per compounds of 0.09 seconds. The S 1 and T 1 excitation energies are fairly reproduced with (Figure ) 𝑅 2 of 0.66 and 0.70 against ADC(2), respectively. As seen in Figure , the Δ𝐸 ST at the SCF + DSP level shows a moderate 𝑅 2 of 0.46, which increases significantly to 0.71 at the CIS + DSP level (Figure ). However, due to a systematic overestimation of Δ𝐸 ST , the F1 score is still low at 0.27 and the recall is only 0.16 (Table ). We therefore added a linear correction Δ𝐸 DSP ST,CIS,LC = 0.53 ×Δ𝐸 DSP ST,CIS -0.15, which increases the F1 score to 0.55 and the recall to 0.51 (Figure ). The specificity simultaneously decreases from 0.99 to 0.96, but overall the linear correction would be preferable for virtual screening where there is a strong focus on finding rare hits. Applying the linear correction to the azaphenalenes (Figure ) and azaazulenes (Figure ) leads to an improvement in the recall of the former from 0.56 to 0.94 while still none of the inverted azaazulenes are recovered. The oscillator strengths are unfortunately poorly correlated for the rational design set, with 𝑅 2 = 0.21, although the Spearman rank correlation is more encouraging at 0.58 (Figure ). Taken together, the results reinforce the conclusions from the case study of the azaphenalenes, that the PPP protocol is suitable for screening Δ𝐸 ST while it struggles for oscillator strengths.