To determine stationary excited states of the molecules, CIS and LR-TDHF calculations were performed. The resulting excitation energies, and x-axis components of excited state and transition dipole moments are listed in Table for state S 1 (total dipole moments are given in the SI). Given the same ground state, the S 0 dipole moments for the three molecules are the same across the two methods. The large difference in ground S 0 and excited S 1 state dipole moments (consistently > 1 debye across the set of molecules) indicates that S 1 is a chargetransfer state. The magnitude of the dipole moment of S 1 increases as the system size increases. This increase is, however, larger for excited state dipole moments calculated using CIS compared to TDHF. The difference in discrepancy between excited state dipole moments decreases as the system size increases. The charge-transfer excitation energies calculated using the linear response methods decrease in value with increasing system size with the corresponding S 0 → S 1 density-difference plots show an increase in electron density in the π-cloud and a decrease around the N-center in the molecules (Fig. ). Table lists the composition of the S 0 → S 1 transition for the three molecules calculated in terms of oneelectron transitions between orbitals. For System 1, the transition is primarily characterized by a HOMO → LUMO transition, with small contributions from other one-electron transitions. With increasing system size the one-electron transitions involving the frontier orbitals beyond the HOMO and LUMO contribute to slightly higher extents, but the electronic character of the transition across the three molecules is primarily of a one-electron HOMO → LUMO transition for both excited state methods. Corresponding density-difference plots show similar nature of re-distribution of the electron density upon excitation from the ground state S 0 to S 1 .