Solvent Hierarchy in Hydrogen‐Bonded Organic Frameworks Enables Orthogonal Stability and Dynamic Responsiveness

ABSTRACT Solvents in crystalline materials typically exist either as structural components that stabilize the framework or as adsorbed guests that modulate properties, yet achieving their orthogonal coexistence within a single system remains challenging. This study proposes a natural mineral‐inspired solvent hierarchy strategy that enables the concurrent achievement of framework stability and dynamic responsiveness in hydrogen‐bonded organic frameworks (HOFs) through the orthogonal integration of structural and adsorbed solvents. We have validated the feasibility of this solvent hierarchy approach based on four model systems with progressively increasing stability and dynamism: (1) unstable HOFs containing only adsorbed solvents, (2) unstable HOFs with low‐binding‐energy structural solvents, (3) stable HOFs incorporating strong‐fitted structural solvents, and (4) stable HOFs with structural solvents and dynamically adjustable adsorption solvents. Crystallographic and theoretical analyses reveal that the superior stability of structural solvents originates from the high‐electron‐density oxygen of the DMSO S═O bond, which acts as a strong hydrogen‐bond acceptor, forming stable N─H···O═S bonds with amine groups. The host's aggregation‐induced emission (AIE) characteristics allow real‐time optical monitoring of reversible single‐crystal‐to‐single‐crystal transformations without compromising structural integrity, demonstrating promising applications for visual water content and water leakage detection. This work not only establishes a new paradigm in solvent engineering for developing smart crystalline materials but also expands the design possibilities for functional porous frameworks.