In contrast with RIR-type AIEgens that frequently demand lengthy organic synthesis procedures for ring-closing, substitution, and rotor grafting, it is highly attractive for researchers to explore the formation of twisting structures through uncomplicated modification of existing fluorescent molecules. An example would be the utilization of coumarin as the backbone to contrived derivatives and introducing aliphatic rings of differing pliability . The coumarin derivative without a rotor and with the heptacyclic aliphatic ring (CD-7) exhibited typical AIE features. However, its analog with the pentacyclic aliphatic ring (CD-5) displayed a contrasting aggregation-caused quenching (ACQ) effect (Figure ). The variation in the saturated alkyl ring size leads to concomitant changes in flexibility, resulting in distinct photophysical curve behaviors (Figure ). This unusual sight is likely due to the out-of-plane intramolecular vibration of the large aliphatic ring unit in solution.