The design and synthesis of a novel supramolecular allosteric catalyst, assembled via the weak-link approach, is presented. The catalyst shows completely reversible allosteric regulation for the catalytic cleavage of 2-(hydroxypropyl)-p -nitrophenyl phosphate (HPNP), which is an RNA model substrate. The system works under pseudo-aqueous conditions and can be turned completely off due to a bridging acetate ligand in the deactivated state, which inhibits the analogous intermolecular catalytic process.