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Pumping ions against a concentration gradient through protein-based transporters is a cornerstone of numerous biological processes. Mimicking this function by using artificial receptors remains a daunting challenge, mainly because of the difficulties in balancing between the requirement for high binding affinities and precise and on-demand ion capture and release properties. We report a trimeric hydrazone photoswitch-based receptor that converts light energy into work by actively transporting chloride anion against a gradient through a dichloromethane liquid membrane, functioning as a molecular pump. The system manifests ease of synthesis, bistability, excellent photoswitching properties, and superb ON-OFF binding properties (difference of up to six orders of magnitude). 

Visible-light-absorbing photoswitches based on the Azo-BF₂scaffold show reversible isomerization in the solid state, storing photon energy and releasing thermal energy on demand. 

Abstract Developing responsive coatings and materials requires discovering a breadth of mechanisms by which external stimuli can be converted into useful signals. Here, we demonstrate an approach driven by supramolecular mechanochemistry, where mechanical input—molecular shape change—is translated into structural color variation. By embedding bistable, negatively photochromic hydrazone photoswitches into cholesteric polymer networks, we achieve a reversible, stable color shift through molecular‐scale pulling and pushing of the photonic scaffold. Unlike azobenzene‐based systems, which typically disrupt liquid crystal order, this approach modifies the pitch of a cross‐linked cholesteric helix without disrupting the organisation of the material. The long‐lived stability of both hydrazone isomers ensures durable optical switching. This effect provides a new strategy for designing mechanoresponsive photonic coatings and tunable optical materials. 

BF 2 -based fluorophores, such as the well-known BODIPY (4,4-difluoro-4-bora-3 a ,4 a -diaza- s -indacene) dye, are prevalently used in diverse research areas ( e.g. , bioimaging and chemosensing) as they exhibit promising features including high quantum yields, fine-tuned absorption and emission spectra as well as good photostability and biocompatibility. While BODIPY dyes are most commonly used in such applications, other BF 2 -based fluorophores, such as BOPHY (bis(difluoroboron)-1,2-bis((1 H -pyrrol-2-yl)methylene)hydrazine – which possess their own characteristic features – are rising in popularity and are being used in a range of applications spanning from molecular sensors to photosensitizers for solar cells. This review examines select examples of BOPHY dyes to highlight the progression of their development while detailing their syntheses and photophysical properties including structure–property relationships. Applications of a number of substituted BOPHYs made by the methods described in this review are also presented.