Molecular‐Scale Geometry Switching for Proton‐Driven Macroscopic Actuation

A conceptual framework for mechanical actuation is presented, rooted in molecular‐level structural switching via ligand isomerization around a central metal ion. During the α to β ligand geometric switching, intramolecular hydrogen bonding, a key attractive interaction, is dismantled, dramatically enhancing proton charge localization and its spatial organization. This structural realignment in the β isomer results in a threefold increase in anion population at the electric double layer, unleashing a fundamentally unique proton‐driven mechanical response. Unlike conventional methods, this mechanism offers an unexplored dimension, translating precise molecular reconfigurations into macroscopic motion. This work highlights how molecular‐level structural switching can serve as a design principle for creating highly responsive, adaptable soft actuators, paving the way for advances in soft robotics, molecular machinery, and dynamic materials.