Dual‐Guest Functionalized Zeolitic Imidazolate Framework‐8 for 3D Printing White Light‐Emitting Composites

Abstract Metal–organic frameworks (MOFs) stand as a promising chemically active host scaffold for the encapsulation of functional guests, because they could enhance luminescent properties by molecular separation of fluorophores in the nanoscale pores of the MOF crystals. Herein, simultaneous nanoconfinement of two fluorophores is shown, namely, A) fluorescein and B) rhodamine B in the sodalite cages of ZIF‐8, constructed under ambient conditions through a simple one‐pot reaction. A novel Dual‐Guest@MOF system is reported, termed: A+B@ZIF‐8, which overcomes the intrinsic problem of aggregation‐caused quenching in the solid state to gain bright yellow emission under UV irradiation. Subsequently, this yellow emitter is combined with a blue‐emitting photopolymer resin, to yield a 3D printable luminescent composite material. A number of 3D printable composite objects for converting UV into warm white light emission are designed, achieving a high quantum yield of ≈44% in the solid state 3D printed form. This research instigates the bespoke application of a vast range of 3D printable Guest@MOF designer composites targeting energy‐saving lighting devices, smart sensors, and future optoelectronics.