Molecular Cage with Dual Outputs of Photochromism and Luminescence Both in Solution and the Solid State.

The rational design of stimuli-responsive materials requires a deep understanding of the structure-activity relationship. Herein, we proposed an intramolecular conformation-locking strategy─incorporating flexible tetraphenylethylene (TPE) luminogens into the rigid scaffold of a molecular cage─to produce a molecular photoswitch with dual outputs of luminescence and photochromism in solution and in the solid states at once. The molecular cage scaffold, which restricts the intramolecular rotations of the TPE moiety, not only helps to preserve the luminescence of TPE in a dilute solution but facilitates the reversible photochromism on account of the intramolecular cyclization/cycloreversion reactions. Furthermore, we demonstrate assorted applications of this multiresponsive molecular cage, e.g., photo-switchable patterning, anticounterfeiting, and selective vapochromism sensing.