Finally, we computed quantum yields of the trans → cis isomerization. They are summarized in Tab. 1. At the CIS level, we find Φ ≈ 17 % and Φ ≈ 16 % for the monomer and the ring, respectively. At the CISD level, the quantum yields are higher: Φ ≈ 22 % and Φ ≈ 34 % for the monomer and the ring, respectively. Moreover, at the CISD level, the quantum yield for trisazobenzenophane is higher than that for the monomer, whereas similar quantum yields are obtained for both systems at the CIS level. Normally, if a trajectory is reactive, only one azobenzene unit undergoes isomerization (Fig. ). Some trajectories, however, exhibit upward hops from S 0 (after initial internal conversion to S 0 ) which may result in switching of the second unit (Fig. ). One trajectory with back hops (at the CISD level) demonstrates isomerization of all three azobenzene units (Fig. ). Moreover, at the CISD level, five trajectories are trapped in a state with two CNNC angles oscillating near 90-100 • (and the third one staying at ∼180 • ), see Fig. .