We reported the photoluminescence (PL) and scintillation characteristics of various organic–inorganic perovskite-type compounds having a diamine: (H3NC5H10NH3)PbBr4 (1-5DIP), (H3NC6H12NH3)PbBr4 (1-6DIH), (H3NC10H20O2NH3)PbBr4 (BBE), and (H3NC10H20O3NH3)PbBr4 (DGBE). In the PL spectra, an emission peak derived from free excitons in the inorganic layer was detected at approximately 410 nm (1-5DIP) and 400 nm (1-6DIH, BBE, and DGBE). Quantum yields of the 1-5DIP, 1-6DIH, BBE and DGBE crystals were 0.2%, 6.0%, 4.0%, and 4.2%, respectively. A scintillation peak originating from exciton emissions appeared at around 430 nm (1-6DIH, BBE and DBE), and 440 nm (1-5DIP) under X-ray radiation. Further, their pulse height spectra were recorded under 241Am gamma-ray irradiation, and their scintillation light yields were 4400 photons/MeV (1-6DIH), 1400 photons/MeV (BBE), and 1700 photons/MeV (DGBE), whereas the yield of the 1-5DIP was not obtained.