Solvent‐Driven Reversible Phase Transition of a Pillared Metal–Organic Framework

Abstract Over the last decade, the controllable reversible phase transition of functional materials has received growing interest as it shows unique suitability for various technological applications. Although many metal–organic frameworks (MOFs) possess a lamellar structure, the reversible structural transformation of MOFs between their three‐dimensional (3D) phase and two‐dimensional (2D) phase remains a largely unexplored area. Herein, we report for the first time a europium MOF with unprecedented reversible morphology in different solvents at room temperature. This europium MOF displayed a 3D nanorod morphology in organic solvent and a 2D nanobelt architecture in water. As a proof of concept for potential applications of this reversible‐phase‐transition MOF, we were able to use a delamination recovery method to load dye molecules that previously could not be loaded into europium MOFs.