High light yield, low detection limit, large X-ray attenuation efficiency and nontoxic composition are critical features of scintillators for ionizing radiation detection. We herein demonstrated a new layered organic-inorganic hybrid cuprous iodide single crystal (C6H10N2)2Cu2I3(PO2)3 (C6H10N22+ = 1,4-phenylenediaminium) for X-ray detection and imaging. Upon UV light excitation, (C6H10N2)2Cu2I3(PO2)3 displays highly efficient yellow light emission with one dominant peak located at 578 nm, a large Stokes shift of 160 nm, and a high photoluminescence quantum yield (PLQY) of 96.4%. This crystal could also exhibit radioluminescence with a high scintillation light yield of 32 000 photons MeV-1. A detection limit of similar to 39 nGyair s-1 is determined, which is far lower than the required value of 5.5 mu Gyair s-1 for regular medical diagnostics. Moreover, the (C6H10N2)2Cu2I3(PO2)3-based scintillation screen exhibits high-performance for X-ray imaging with a spatial resolution of 11.14 lp mm-1, indicating the great potential in X-ray radiography. In brief, combined merits of low toxicity and cost, negligible self-absorption, a low detection limit, a high light yield and a spatial resolution make (C6H10N2)2Cu2I3(PO2)3 an excellent candidate for X-ray scintillation. A new metal halide single crystal (C6H10N2)2Cu2I3(PO2)3 was demonstrated. The optical and X-ray properties of (C6H10N2)2Cu2I3(PO2)3 were fully characterized and evaluated, which demonstrated great potential for X-ray detection and imaging.