3. a generally applicable extension to excited-state reactivity to deepen the insight into photochemical phenomena and, in the same vein, an extension to timedependent conceptual DFT; 736 4. a deeper connection between conceptual DFT and information theory and its density functionals and with the reaction-force ansatz when considering reaction mechanisms. Recognizing that the ultimate goal of conceptual DFT is prediction, it was realized that the one reactant approach on the basis of the above mentioned E[N, v] expansion should be scrutinized to identify what terms in the expansion of E [N, v] are most likely to be efficient for a given problem, thereby challenging chemical intuition. Characteristics of the second reactant most probably should be explicitly introduced at various levels of refinement for quantifying the ∆N and ∆v perturbations. In contribution (3.7.11), I described MS-DFT as a hybrid wave-function and DFT method in the context of ensemble DFT. The basis states used to generate the energies of the adiabatic states in the ensemble can be viewed as effective valence-bond configurations. These configurations, obtained either through fragmental block-localization or by local electronic excitations, correspond to well-defined Lewis resonance structures, whose variational optimization can be directly used for block-localized wave-function interaction energydecomposition analysis (BLW-EDA) to provide a quantitative interpretation of DFT results, such as aromaticity, hyperconjugation, and the Dewar-Chatt-Duncanson σ -dative donation and π-backbonding in transition-metal complexes. Furthermore, these localized electronic structures can be used to define diabatic states by orthogonal projection, 740 suitable for dynamics simulations of nonadiabatic processes, including electron transfer, excited-state energy transfer, and photochemical reactions.