For both molecules, as expected, single and triple CI marginally contribute to the ground state (according to the Brillouin theorem in fact single and triple CI are not directly mixed to the ground state configuration, and marginally contribute to it via their indirect mixing to double CI). As for excited states, in both molecules, double and triple CIs enter the picture with a similar and sizable weight. This is a strong indication that a reliable approach to the excited states of these molecules should include at least triple CIs. On the other hand, the weight of quadruple CIs stays very small, suggesting that fourth and higher order CIs can be safely neglected.