The Cover Feature shows trains travelling on a track: the engine (HaloTag) and wagon (eDHFR) are linked by a photoswitchable molecular coupler based on an azobenzene photoswitch. Blue light uncouples them, while green light restores binding. The infinity-shaped track symbolizes reversible control. More information can be found in the Concept by Y.-W. Wu and co-workers (DOI: 10.1002/cptc.202500267). Cover illustration by Ida Åberg.
Herzog et al. (Sun,) studied this question.