BOIMPY Scaffold: Accessing Ultrahigh Molar Extinction Coefficient AIEgen for SWIR Imaging‐Guided Photothermal Cancer Ablation

Abstract Despite the extensive reporting of versatile aggregation‐induced emission luminogens (AIEgens), boosting their molar extinction coefficient (MEC, ε ≈ 10³–10⁴ M⁻¹cm⁻¹) remains a formidable challenge, which poses a significant obstacle to achieving the ceiling of their output performance. In this work, an “aggrandizing absorption reservoir” approach is proposed to designing AIEgens with remarkable photons‐harvesting ability, ultimately enlarging its output performance in terms of short‐wave infrared (SWIR, 900–1700 nm) emission and photothermal effect. For the first time, the (bis‐(borondifluoride)‐8‐imidazodipyrromethene) (BOIMPY) unit, which provides sufficient rigidity and strong electron‐withdrawing ability by employing benzimidazole as a bridging ligand binding two BF₂ units, is utilized to fabricate novel AIEgen (TPEB) that exhibits an ultrahigh MEC up to 1.29 × 10⁵ M⁻¹ cm⁻¹ at 828 nm. To the best of knowledge, this is the highest MEC reported among AIEgens with near‐infrared absorption. Thanks to its remarkable photon‐harvesting ability, TPEB exhibits strong fluorescence in the SWIR region and a good photothermal effect. The as‐prepared TPEB NPs are successfully applied for SWIR imaging‐guided photothermal antitumor therapy. The proposed “aggrandizing absorption reservoir” approach provides a novel guideline for designing versatile AIEgens for biomedical applications.