Organic–inorganic hybrid manganese halides with low cost, facile synthesis, and high-efficient luminescence have emerged as the novel candidate materials for X-ray detection and imaging. In this work, a series of manganese halides (CP1–CP5) with tetrahedral coordination structures were designed and synthesized by a facile room-temperature evaporation method. All of these complexes exhibit strong green emission around 512 nm, originating from d–d ⁴T₁–⁶A₁ transitions of Mn²⁺ centers, and possess high photoluminescence quantum yields of over 85%. CP1–CP5 exhibit strong radioluminescence under X-ray irradiation, and demonstrate excellent linear response to X-ray dose rate. Among them, CP5 demonstrates the optimal X-ray scintillation performance with a low detection limit of 17.96 nGy_air s⁻¹. Moreover, by employing CP5 film as a scintillator screen, high-resolution X-ray imaging of 4.35 lp mm⁻¹ was accomplished. This work provides a new way for the preparation of simple and low-cost metal halides applied in X-ray imaging.