sets an opposite goalpost as compared to TD-PBE. It exhibits a MAE of 0.51 eV and nearly all of the errors are positive. For comparison, the uncorrelated configuration interaction singles (CIS) method affords strictly positive errors with a MAE of 0.82 eV. Description of the 1 L a transition of the linear acene molecules is a trouble spot for TD-DFT, even with global hybrid functionals. Errors increase as a function of molecular size in a manner that is not observed for the 1 L b state, which is polarized along the opposite axis of the molecule. As compared to either GGA or hybrid functionals, LRC functionals do a much better job at describing both states. Optimal tuning affords especially accurate excitation energies, with MAEs of 0.17 eV (LRC-ω IE PBE) and 0.18 eV (LRC-ω GDD PBE) with respect to experiment, considering the combined data set of 1 L a and 1 L b for naphthalene through hexacene (Table ). For naphthalene, the 1 L b state lies below 1 L a , in contrast to the behavior for the larger acenes, and this is captured by both of the aforementioned LRC functionals but not by PBE, PBE0, or HF-PBE. Most importantly for the present analysis, TD-DFT excitation ener-gies obtained using LRC-ω IE PBE versus LRC-ω GDD PBE differ by an average of only 0.12 eV, which is smaller than the intrinsic accuracy of either method.