Unlike ∆E HL , molecules containing aldehydes (blue) and primary alcohols (pink) exhibit polarizabilities that extend throughout the entire range of the dataset (cf. Fig. ). This finding is further reflected in the average Kolmogorov-Smirnov-metric (measuring the statistical distance between two general distributions, see Sec. II of ESI † ) of the individual molecular classes in the (∆E HL , α)-space, which is 0.81 and 0.40 for ∆E HL and α, respectively. Our analysis then demonstrates that functional groups primarily affect HOMO-LUMO gap rather than the polarizability, resulting in well-defined molecular clusters on the ∆E HL -axis.