Organic　thermally　activated　delayed　fluorescent　(TADF)　scintillators　hold　promising　potential　for　applications　in　medical　radiography　and　security　detection,　but　the　poor　X‐ray　absorption　ability　and　inferior　radioluminescence　(RL)　hampered　their　progression.　Herein,　the　study　has　pioneered　the　development　of　high‐performance　TADF　Ag(I)‐based　scintillators　from　M2X2(dppb)2　(M　=　Ag,　Cu;　X　=　Cl,　Br,　I)　complexes　with　1,2‐Bis(diphenylphosphino)benzene　(dppb)　ligand.　In　comparison　with　Cu(I)　complexes,　the　Ag(I)　series　generally　exhibited　superior　scintillation　performance.　Notably,　Ag2Cl2(dppb)2　(Ag1)　stands　out　with　exceptionally　high　RL　intensity　(≈125%　higher　than　that　of　CsI:Tl)　and　a　low　detection　limit　of　59.8 nGy s−1.　The　outstanding　scintillation　performance　of　Ag1　is　primarily　attributed　to　the　synergistic　effect　of　the　high　exciton　utilization　efficiency　origin　from　a　small　singlet‐triplet　energy　gap,　enhanced　X‐ray　absorption　capacity　by　heavy　atoms,　and　the　high　photoluminescence　quantum　yield　(76.47%　in　ambient　atmosphere).　By　fabricating　a　flexible　film　constructed　with　Ag1　submicron　crystalline　powders,　a　high　spatial　resolution　of　25.0 lp mm−1　for　X‐ray　imaging　is　obtained.　It　offers　new　opportunities　for　utilizing　TADF　metal–organic　complexes　for　highly　efficient　X‐ray　scintillation　and　imaging.