Metallophilicity‐Driven Antagonistic Thermal Responses in Isostructural d ¹⁰ Metal‐Thiolate Frameworks for Programmable Optical Anti‐Counterfeiting

The development of luminescent materials with programmable thermal responses is critical for advanced optoelectronics and encryption, yet achieving precise and opposite regulation between thermal quenching (TQ) and anti‐thermal quenching (ATQ) in isostructural systems remains challenging. Here, the inherent electronic differences between Cu(I) and Ag(I) were exploited to construct two isostructural d 10 thiolate frameworks, [Ag 3 Br 3 (TPY) 2 ] n ( Ag‐TPY , TPY = pyridin‐1‐ium‐2‐thiolate) and [Cu 3 Br 3 (TPY) 2 ] n ( Cu‐TPY ), achieving antagonistic luminescent thermal responses. This approach enables Ag‐TPY to exhibit conventional TQ, while Cu‐TPY features remarkable ATQ, representing the first two‐dimensional copper‐thiolate framework to exhibit such behavior. This thermal dichotomy is complemented by distinct emission colors, from yellow (566 nm) to red (656 nm). Mechanistic studies reveal that the contracted 3d orbitals of Cu(I) enhance covalent bonding and structural rigidity, stabilizing shallow trap states that facilitate ATQ via thermally activated exciton detrapping. In contrast, the diffuse 4d orbitals of Ag(I) promote argentophilicity‐driven distortion and deeper traps, resulting in triplet emission dominated by non‐radiative decay. Leveraging the differences in their emission colors and quenching temperatures, a dynamic information encryption system with multi‐level, temperature‐gated security control is designed. This work establishes metal‐ion selection in isostructural frameworks as a generalizable strategy for the rational design of tunable responsive materials.