Tough Supramolecular Glasses Enabled by Frustrated Non‐Covalent Complexation

Abstract Supramolecular glasses, as noncovalently cross‐linked amorphous materials, are hampered by a fundamental trade‐off between vitrification and mechanical performance. Here we propose a strategy—“frustrated non‐covalent complexation”—inspired by frustrated Lewis pairs to overcome this limitation. This is achieved by installing sterically hindering isopropyl groups adjacent to directional squaramide hydrogen‐bonding motifs. Relative to a nonfrustrated control, this design not only generates more loosely packed hydrogen‐bonded domains but also shifts the dominant interactions from squaramide–squaramide to squaramide–ester hydrogen bonding. The frustrated system yields a 4.3‐fold increase in mechanical toughness in the resulting supramolecular glass, facilitated by efficient energy dissipation through reversible hydrogen‐bond rupture. It also enhances interfacial adhesion, functioning as an effective impact‐resistant coating that mitigates substrate fracture. Overall, this work establishes frustrated noncovalent complexation as a powerful paradigm for designing high‐performance supramolecular glass materials.