Yang et al. followed a different research axis and looked into the impact of the presence of molecular rotors on the separation properties of the framework itself, i.e., focus on the influence of the rotors on the adsorbates. In the SNNU-118 MOF, the combination of the rotational flexibility of the molecular rotor and rotor-guest interactions lead to a gate-opening effect. Moreover, the difference in the nature of the linker-CO 2 and linker-C 2 H 2 interactions leads to a favorable separation of C 2 H 2 /CO 2 gas mixtures.