X-ray　imaging　utilizing　organic–inorganic　hybrid　metal　halide　(OIHMH)　glassy　scintillators　has　garnered　significant　attention.　But　their　inferior　radioluminescence　makes　achieving　rapid　image　acquisition　difficult,　posing　a　persistent　challenge　for　dynamic　imaging.　Herein,　organic　phosphonium　halide　side-chain　engineering　is　proposed,　introducing　bulky　aromatic　rings　at　the　alkyl　chain　ends,　to　improve　the　radioluminescence　of　OIHMHs.　For　Mn(II)-based　OIHMHs,　the　(BUP)2MnCl4　(BUP　=　butyltriphenylphosphonium)　powder　has　a　low　relative　light　yield　(5400　photons　MeV−1).　After　introducing　a　benzyl　group,　this　value　of　(BnO-MTP)2MnCl4　(BnO-MTP　=　(benzyloxy)methyl)　triphenylphonium)　powder　boosts　to　60 000　photons　MeV−1.　The　introduction　of　benzyl　group　can　restrict　molecular　non-radiative　vibrations,　increase　exciton　binding　energy,　enhance　electron-phonon　coupling,　and　reduce　self-absorption,　thus　significantly　improving　exciton　utilization　and　scintillation　performance　of　(BnO-MTP)2MnCl4.　Besides,　the　transparent　(BnO-MTP)2MnCl4　glass　has　a　low　melting　point　(167 °C)　and　high　relative　light　yield　(26 000　photons　MeV−1).　When　applied　to　X-ray　imaging,　it　can　achieve　static　imaging　with　a　spatial-resolution　of　up　to　24.6　lp　mm−1　and　clear　dynamic　imaging　under　X-ray　irradiation.　Furthermore,　this　strategy　also　applies　to　Sb(III)-based　OIHMHs　with　self-trapped　exciton　emissions,　where　(BnO-MTP)2SbCl5　exhibits　superior　scintillation　performance　compared　to　(BUP)2SbCl5,　demonstrating　its　broad　applicability　in　constructing　high-performance　OIHMH　glassy　scintillators.　©　2024　Wiley-VCH　GmbH.