Photodetectors play a key role in the military, aerospace, communications, bio-imaging, etc. In this study, we fabricate photodetector devices based on (CH₃NH₃)₂FeCuI₄Cl₂ (MA₂FeCuI₄Cl₂) and (CH₃NH₃)₂InCuI₆ (MA₂InCuI₆) for the first time. We find that the device based on MA₂InCuI₆ is highly selective for ultraviolet light (880 nA mW⁻¹) and shows high anti-interference for visible-light (20–50 nA mW⁻¹). The electrochemical impedance results indicate that the value (480 ± 10 Ω) of the resistance based on the MA₂InCuI₆ photodetector device is much smaller than that (1 ± 0.001 MΩ) based on the MA₂FeCuI₄Cl₂ photodetector device, which in turn proves the difference in photoelectric response.