A mechanism for the distortivity of π-systems was uncovered in seminal work by Shaik and co-workers using valence bond theory, and by Heilbronner and co-workers using Hückel method calculations. There is a balance between the σsystem's rigidity and the π-system's distortivity, which are both molecule-dependent. Pentalene is a textbook example of the distortion into a double-bond localized structure (from D 2h to C 2h symmetry), and its distortion correlates with a reduction in the antiaromaticity of the molecule. The balance between πdistortivity and σ -rigidity can be pushed towards double-bond delocalization, and several substituted pentalenes and structurally analogous indacenes assume high symmetry in their crystal structures. Several alternative explanations to double-bond delocalization in crystal structures have been suggested, and the assignment of the correct global minimum structures continues to be a computational challenge when the energy difference is small. Considering the ongoing challenge of assessing the true global minimum energies, our focus here is to assess excited-state energy ordering in substituted molecules where double-bond localization is minimized.