version. The primary difference between the two compounds is that the magnitude of the transition dipole moment between the ground state and the CT state is nearly zero in the DQI compound (27N). This difference follows directly from the graphical model that predicts QI conditions: optical excitation within the PPP Hamiltonian conserves spin symmetry, and optically allowed CT processes can occur only between sites that are antiferromagnetically coupled. We have done detailed analyses of the correlated-electron exciton basis wavefunctions of the optically allowed excited states for all compounds (Table ). The corresponding analysis for P-26N-P reveals an identical story.