Synergistic Enhancement of Ligand & Cluster Connectivity to Construct Highly Stable Fluorescein‐Based MOFs with Thickened Channel Walls for Boosting Photocatalytic Activity

Abstract Fabricating visible‐light‐responsive metal−organic frameworks (MOFs) with high stability and effective catalytic functionality remains a long‐term pursuit yet a great challenge. Herein, a strategy of increasing ligand and cluster connectivity is developed to construct highly stable fluorescein MOFs, La‐CFL, presenting a new (4,8)‐connected topological structure compared to Cd‐FL constructed using 6‐connected dinuclear clusters and 3‐connected tritopic ligands. La 8 (CFL) 4 containers like Chinese “Ritual Wine Vessels (Jue)” resemble linear arrangements interconnected by the [La 2 (COO) 4 ] clusters. This arrangement induces benzene rings and xanthene rings to locate on the inner walls of 1D channels, resulting in thicker channel walls that contribute to enhanced stability. Consequently, La‐CFL demonstrates outstanding catalytic performance in thiol–ene reactions under green LED irradiation. It exhibits 2.3 times higher efficiency than Cd‐FL while reducing reaction time to one‐fifth at 20 min. Furthermore, La‐CFL displays size‐selective catalysis and retains full activity for 20 cycles without degradation, an improvement over Cd‐FL's recyclability limitations.