Nanocluster‐Stabilized Sulfur‐Based Superradical with High Photothermal Performance and NIR‐II Emission

Abstract The stabilization and multifunctionalization of radicals constitute two major challenges. We introduce a “kill two birds with one stone” methodology and illustrate the production of Au 64 (CPT) 31 S· from the newly obtained precursor nanocluster Au 64 (CPT) 32 (CPT: cyclopentanethiolate). Despite the isolated Au 64 (CPT) 31 S· are ultrastable (maintain the majority under 100 °C for 2 h in an atmospheric solution environment), they can initiate the polymerization of pentaerythritol triacrylate in 3D printing. In addition, the superradicial(which means it is not a single (super)atom but a complex system with superstability) exhibited NIR‐II emission, as well as high photothermal conversion efficiencies of 82.9% and 65.1% under 532 and 980 nm laser irradiation, respectively. Therefore, this study can serve as a foundation for novel superradical studies and applications and the findings hold notable implications for radical stabilization, multifunctionalization, and structure–composition–property correlations.