Evolution trains a from-scratch catalyst: Metal-bound peptides can catalyze simple reactions such as ester hydrolysis and may have been the starting point for the evolution of modern enzymes. Studer et al. selected progressively more-proficient variants of a small protein derived from a computationally designed zinc-binding peptide. The resulting enzyme could perform the trained reaction at rates typical for naturally evolved enzymes and serendipitously developed a strong preference for a single enantiomer of the substrate. A structure of the final catalyst highlights how small, progressive changes can remodel both catalytic residues and protein architecture in unpredictable ways. Science , this issue p. 1285

Molecular photoswitches reversibly convert the energy of light into a variety of structural changes at the molecular level. They can be integrated into smart materials with broad range of applicability. While most photochromic systems require UV light for activation, application of photoswitches operational entirely within the visible or NIR range of light brings considerable benefits, such as biocompatibility, better light penetration through the material, propelling with sunlight, or a possibility to design dual systems that are mutually activated with UV or visible light frequencies for two distinct functions. In this Review, we discuss the most relevant classes of molecular photoswitches, and demonstrate a selection of photochromic polymers, gels, porous materials, surfaces, energy‐storing materials and other systems triggered with visible light.