The cover illustrates the chiral self-sorting and adaptive host-guest behavior of flex-COP-n, a new family of flexible covalent organic pillars with deep-cavity architectures (e202509177). These nanotubular hosts form enantiomeric or meso duplexes via dynamic imine condensation and accommodate guest molecules through mutual deformation. Cartoon springs and character-filled cavities depict how host and guest adjust their shapes to achieve precise molecular recognition, echoing biological receptors.