Vertical excitation energies for all molecules were initially computed at the second-order approximate coupled-cluster level (CC2) using Turbomole 7.1. CC2 provides a good compromise between between computational accuracy and efficiency, which allows us to compute excitation energies of potentially thousands of molecules. For molecules with negative gaps at the CC2 level, we further compute the excitation energies at the equations-of-motion coupled-cluster level (EOM-CCSD) with the QChem 5.1 package. Depending on the size of the molecule, the aug-cc-pVDZ or cc-pVDZ basis set is applied. Based on molecules for which it is possible to compare both basis sets, the addition of augmented basis functions makes only a small difference in most cases (Figure ).