This study includes 30 organic molecules containing from 1 to 6 non-hydrogen atoms, see Scheme 1. The correspond- ing geometries, optimized at the CC3/aug-cc-pVTZ level, were extracted from prior works, and are provided in the SI. We consider low-lying singlet excited states having valence or Rydberg character, as well as several states with non-negligible contributions from double excitations. All molecules studied belong to a symmetry group higher than 𝐶 1 . Therefore, each excited state is identified by its irreducible representation, and their ranking starts from the lowest excited state, excluding the ground state in the numbering. For example, the first excited state of acrolein is denoted as 1𝐴'.