jats:titleAbstract</jats:title>jats:pA new type of composite material involving the in situ immobilization of tin oxide nanoparticles (SnOjats:sub2</jats:sub>‐NPs) within a monolithic metal–organic framework (MOF), the zeolitic imidazolate framework (ZIF)‐8 is presented. SnOjats:sub2</jats:sub>@jats:submono</jats:sub>ZIF‐8 exploits the mechanical properties, structural resilience, and high density of a monolithic MOF, while leveraging the photocatalytic action of the nanoparticles. The composite displays outstanding photocatalytic properties and represents a critical advance in the field of treating toxic effluents and is a vital validation for commercial application. Crucially, full retention of catalytic activity is observed after ten catalytic cycles.</jats:p>