Boosting X‐Ray Imaging with a Highly Emissive Steroidal Gold Cluster Featuring Aggregation‐Induced Circularly Polarized Luminescence

Abstract X‐ray imaging is essential for safety inspections, disease diagnosis, and treatment. High‐performance X‐ray scintillators require high luminous efficiency and excellent contrast enhancement. Circularly polarized luminescence (CPL) materials effectively suppress crosstalk and enhance image contrast. Herein, a novel hexanuclear chiral gold cluster ( Cluster‐ETH ) with steroidal ethisterone frameworks is presented. The rigidity‐engineered AIE cluster achieves high quantum yield (84.9%) and an intense CPL signal with a g _lum value of −5.3 × 10 ⁻³ in the aggregated state. Crystal analysis and TD‐DFT calculations show that helical packing via hydrogen bonding interactions and aurophilic interactions drives efficient triplet harvesting. Cluster‐ETH enables the first chiral gold cluster scintillator for X‐ray imaging, demonstrating a low‐detection‐limit (118 nGy s ⁻¹ ). Cluster‐ETH establishes the novel application of chiral gold clusters in advanced imaging technologies, providing a paradigm for the development of efficient X‐ray scintillators.