Aggregation‐Induced Bio‐Based Dimers from Coumarin with Force‐Activated Thermochromism toward Dynamic Information Encryption

ABSTRACT With the deepening mechanistic understanding of intermolecular spatial interactions, dimers, the simplest and most fundamental aggregated architecture, emerge as a versatile platform for the rational design and development of high‐performance aggregated luminescent materials. Herein, we report that a specific class of coumarin derivatives with dihydrazide units spontaneously forms the biomass‐based dimers in both aggregated and solid states, exhibiting pronounced red‐shifted emissions. Mechanistic investigations further reveal that these well‐defined dimeric assemblies come from molecular planarization induced by dihydrazide and salicyl units, heteroatom‐involved spatial interactions, and steric hindrance imposed by chlorine atoms, which synergistically orchestrate the aggregation‐induced red‐shifted emission. Notably, these coumarin‐derived dimers exhibit an intriguing force‐activated thermal responsiveness. Mechanical force modulates the packing modes of dimeric assemblies, enabling reversible thermochromic fluorescence. As a practical demonstration, coumarin derivatives integrating both thermochromism and acidichromism are successfully employed for dynamic information decryption, highlighting their potential in intelligent anti‐counterfeiting. This work successfully constructs high‐performance aggregated luminescent materials based on biomass‑based dimers and exploits their unique force‑activated thermochromic responsiveness to extend applications in intelligent anti‑counterfeiting.