Organic　scintillators,　pivotal　in　security　and　medical　applications,　face　challenges　due　to　limited　X-ray　absorption　and　exciton　utilization.　Herein,　a　novel　class　of　organic　scintillators　is　introduced,　named　guest-induced　thermally　activated　delayed　fluorescence　(TADF)　within　supramolecular　macrocycles　via　host-guest　through-space　charge　transfer　(TSCT).　Four　co-crystals　are　obtained　through　orthogonal　crystallizations　involving　calix[3]acridan　(C[3]A)　and　calix[3]phenothiazine　(C[3]P)　macrocycles　as　hosts,　along　with　1,2-dicyanobenzene　(DCB)　and　4-bromo-1,2-benzenedicarbonitrile　(BrDCB)　as　guests.　Interestingly,　DCB@C[3]A　and　BrDCB@C[3]A　co-crystals　exhibit　strong　host-guest　TSCT　with　reduced　single-triplet　energy　gap　for　efficient　TADF　emission,　which　leads　to　enhanced　exciton　utilization　and　X-ray　absorption,　yielding　radioluminescence　intensities　over　29　and　25　times　higher　than　C[3]A.　Similarly,　substituting　C[3]A　with　C[3]P,　the　obtained　TADF　co-crystals　also　outperform　C[3]P　in　scintillation　performance.　Additionally,　the　scintillation　color　of　co-crystals　can　be　adjusted　by　varying　the　electron-donating　abilities　of　macrocycles　and　the　electron-accepting　abilities　of　guests,　offering　a　simpler　color-tuning　mechanism　than　covalent-bonded　scintillators.　Furthermore,　the　flexible　film　based　on　DCB@C[3]A　exhibits　promising　application　in　X-ray　radiography,　showcasing　a　high　spatial　resolution　of　20　lp　mm−1　@MTF　=　0.77.　The　innovative　strategy　of　fabricating　organic　scintillators　via　reversible　non-covalent　interactions　presents　a　novel　solution　for　designing　color-tunable　and　high-performance　scintillators.　©　2024　Wiley-VCH　GmbH.