“…In this framework, lead halide perovskite NCs (LHP-NCs) have rapidly garnered particular interest ,,,− due to their high emission yield, radiation hardness, , defect tolerance, and unmatched scalability via room-temperature synthesis methods . This unique combination of chemical and physical advantages has driven a large number of studies encompassing X-ray imaging, − fast timing, ,,,, and therapy applications as well as the detection of γ rays and neutrons. ,, Despite substantial advancements, as of today, the near totality of studies in this area has focused on green-emitting CsPbBr 3 NCs, ,,,, with fewer investigations dedicated to their red-emitting iodine-based counterparts (mostly as single crystals or films for γ detection). − Most surprisingly, there has been no study to date that has addressed the scintillation properties of CsPbCl 3 NCs, which feature size tunable ultrafast emission in the UV-blue , and would thereby extend the spectral tunability of LHP-based nanocomposite scintillators to the typical spectral region of molecular scintillators such as 1,4-bis(5-phenyloxazol-2-yl) benzene (POPOP) (λ EM ≈ 410 nm) and p -terphenyl (λ EM ≈ 350 nm) that match the peak efficiency of bialkali photodetectors widely used in HEP experiments (e.g., Hamamatsu R9880U-210, see Figure S1 in the Supporting Information). , Further CsPbCl 3 NCs have the potential to serve as high- Z sensitizers for secondary molecular emitters in the green spectral region that typically suffer less radiation damage than the more energetic blue-emitting counterparts.…”