Rylene　diimides　are　an　attractive　class　of　organic　dyes　owing　to　their　exceptional　optical　properties　and　optoelectronic　applications.　Herein,　we　extend　their　applications　to　the　realm　of　X-ray　imaging.　The　emissive　1,1′-bi(2-naphthol-4,5-dicarboximide)　(BiND-OH)　and　its　phenyl/methyl　derivatives,　BiND-OPh　and　BiND-OMe,　have　been　selected　to　investigate　the　structure-activity　relationships　between　their　crystal　packing　and　X-ray　scintillation　properties.　Single　crystal　X-ray　diffraction　results　indicate　that　BiND-OH　forms　a　tightly　structured　conformation　with　two　interlocks　by　hydrogen　bonding,　leading　to　a　charge　transfer　state　and　resulting　in　nearly　non-scintillation.　In　contrast,　the　radioluminescence　intensities　of　BiND-OPh　and　BiND-OMe　have　increased　by　about　73　and　537　times,　respectively,　owing　to　the　disruption　of　hydrogen　bonding　control　and　the　formation　of　a　J-aggregation　fraction　dominated　by　π-π　interactions.　Remarkably,　BiND-OMe　displays　superior　scintillation　properties,　marked　by　reduced　non-radiative　transitions,　attributed　to　greater　π-π　plane　distances,　extended　slip　distances,　and　diminished　π-plane　overlap　areas.　It　demonstrates　a　low　detection　limit　of　70.68　nGy　s−1　and　a　short　decay　time　of　4.37　ns.　When　applied　to　X-ray　imaging,　it　produces　a　high　spatial　resolution　of　11.0　lp　mm−1.　This　finding　provides　valuable　insights　into　the　profound　impact　of　molecular　structure　and　aggregation　state　on　the　organic　scintillation　properties.　(Figure　presented.)　©　Science　China　Press　2024.