Fernández Labandeira, NataliaRemón, PatriciaCastellano, RaúlTouriño-Pardo, MaríaGarcía, Marcos D.Pischel, UweBlanco-Gómez, ArturoPeinador, Carlos2026-09-302026-09-302026-08-04Natalia Fernández-Labandeira, Patricia Remón, Raúl Castellano, María Touriño-Pardo, Marcos D. García, Uwe Pischel, Arturo Blanco-Gómez, Carlos Peinador; Self-assembled hydrazone-derived macrocycles show cucurbit[8]uril-assisted tunable excimer-like emission. Org. Chem. Front. 2026; 13 (18): 6186–6194. https://doi-org.accedys.udc.es/10.1039/d6qo00793g2052-41292052-4110https://hdl.handle.net/2183/49521[Abstract] Enforced chromophore proximity provides a powerful molecular design principle to reshape excited-state interactions and tune emission. In this work, we report the optical properties of two self-assembled cyclophanes in which the interplanar distance between the longitudinal bispyridinium chromophores is sufficiently short to promote intramolecular interactions. Both cyclophanes were efficiently synthesized through acid-catalyzed hydrazone condensation in water without the need for a templating effect, highlighting their high preorganization for cyclization. Photophysical studies in acetonitrile revealed clear excited-state interchromophoric interactions in both systems. The cyclophane containing the more conjugated bispyridinium unit (o-REx 4+) displayed a pronounced red-shifted emission (91 nm) and a nearly ninefold increase in emission efficiency relative to its monomeric counterpart. In contrast, chromophoric interaction in the less conjugated cyclophane (o-R4+) induced fluorescence of an otherwise non-emissive bispyridinium chromophore. The emissions are strongly quenched in water, however, complexation with cucurbit[8]uril (CB[8]) restores the fluorescence of both cyclophanes through the formation of stabl ring-in-ring host–guest complexes. These results highlight an efficient synthetic approach to highly preorganized cycl phanes and demonstrate how solvent effects and CB[8] complexation can be exploited to modulate and recover the fluorescence of intramolecular chromophore dimers.engAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/journal articleopen access10.1039/d6qo00793g