An ultra-stable vinylene-linked covalent organic framework for the olefination of fluorene under green light

), exceptional chemical stability in acidic and basic media for up to 30 days, and excellent light-harvesting capability. Leveraging these properties, TMT-DMTD COF was employed as a reusable, metal-free, heterogeneous photocatalyst for the olefination of fluorene under mild conditions. Unlike conventional approaches that rely on precious-metal homogeneous catalysts operating at elevated temperatures (130-140 °C), this methodology operates at room temperature under green-light irradiation with low catalyst loading, affording a broad range of olefins in good to excellent yields. The protocol demonstrates wide functional-group tolerance, truly mild reaction conditions, and significant catalyst recyclability, representing a meaningful advancement over existing methodologies.