Pressure‐Gated Inverse Steric Enforcement in Coordinated Rotors as Programmable Optical Switching for Hierarchical Information Encryption

Abstract The growing demand for advanced anticounterfeiting systems has accelerated the development of chromic materials with spatially programmable optical properties. However, optical materials exhibiting stimulus‐inversed steric effects remain largely unexplored. Herein, two rationally designed luminescent Pt(II) rotors with tailored steric hindrance are presented that demonstrated unprecedented multistimulus‐responsive chromic switching. In contrast to conventional steric effects where bulkier groups enhance emission, these systems display a distinct pressure‐inverted behavior. The smaller‐hindrance rotor 1 showed 25% pressure‐enhanced phosphorescence (874 → 1092 a.u.), whereas the larger‐hindrance rotor 2 underwent dramatic emission quenching of 85% (6446 → 942 a.u.). Through integration into polymer matrices, flexible smart films are fabricated capable of programmable luminescence switching, which enabled time‐dependent dynamic authentication via stimulus‐responsive emission signatures. The multidimensional control strategy establishes hierarchical security platforms that combine intrinsic material complexity with adaptive anticounterfeiting capabilities through sequence‐dependent, multichannel decoding.