Direct　X-ray　detectors,　which　directly　convert　X-rays　into　electrical　signals　through　semiconductors,　have　higher　space　solution　than　scintillator-mediated　indirect　X-ray　ones　and　are　high　desirable　for　early　cancer　detection　and　other　applications,　but　the　mainstream　commercial　α-Se　detector　is　still　largely　limited　by　high　production　costs,　large　leakage　current　and　low　stability.　This　article　reports　an　easily　prepared,　stable　radiochromic　semiconductive　metal–organic　framework　(MOF),　(MV)[Cd3(tdc)4]∙2H2O　(RCS-1,　H2tdc　=　2,5-thiophenedicarboxylic　acid;　MV2+　=　methyl　viologen　cation)　with　direct　X-ray　detecting　ability.　With　a　large　bulk　resistivity　of　8.40　×　109　Ω　cm,　this　material　ensures　minimal　dark　current　and　low　noise　for　X-ray　detection.　Additionally,　it　exhibits　higher　sensitivity　to　W　Kα　X-rays　(98.58　µC　Gy−1　cm−2)　than　α-Se　(∼20　µC　Gy−1　cm−2).　Meanwhile,　unlike　most　reported　direct　X-ray　detecting　semiconductors,　compound　RCS-1　shows　remarkable　color　change　upon　X-ray　irradiation　owing　to　the　presence　of　photochromism-active　viologen　cations.　This　feature　offers　an　appealing　visual　detecting　ability　to　direct　X-ray　detectors　that　provide　only　the　electrical　signals.　©　2024