In The four most significant outliers, whose molecular structures are shown, are: biphenyl (BIPHEN), benzene (BENZEN), 2',2"',3',3"',5',5"',6',6"'-octaphenyl-p-quinquephenyl (PUNVEA), and hexaphenylbenzene (HPHBNZ03). These compounds are characterized by phenyl rings connected by single C-C bonds, whereas the majority of compounds in the PAH101 set are characterized by extended aromatic systems. Our results indicate that DFT triplet formation energies are fairly reliable as lower-cost descriptors for preliminary screening. However, based on the nature of the outliers, it would be prudent to validate these findings for more diverse materials.