Inside Back Cover: A Dithio Vinylthio C ₂ Synthon Enabling Crystalline and Luminescent Sulfur‐Decorated Polymers

From calcium carbide to glowing polymers: a vinylthio C2 building block derived from calcium carbide enables sulfur-rich materials via light-induced thiol–ene polyaddition. Selective anti-Markovnikov addition inserts regular methylene spacers along the backbone, enforcing chain order and crystallinity. Dense thioether clustering gives rise to nonconventional luminescence within an atom-efficient polymer platform. More information in the Communication (e25801), Hatice Mutlu and co-workers.