There　are　few　reports　about　purely　organic　phosphorescence　scintillators,　and　the　relationship　between　molecular　structures　and　radioluminescence　in　organic　scintillators　is　still　unclear.　Here,　we　presented　isomerism　strategy　to　study　the　effect　of　molecular　structures　on　radioluminescence.　The　isomers　can　achieve　phosphorescence　efficiency　of　up　to　22.8　%　by　ultraviolet　irradiation.　Under　X-ray　irradiation,　both　m-BA　and　p-BA　show　excellent　radioluminescence,　while　o-BA　has　almost　no　radioluminescence.　Through　experimental　and　theoretical　investigation,　we　found　that　radioluminescence　was　not　only　affected　by　non-radiation　in　emissive　process,　but　also　highly　depended　on　the　material　conductivity　caused　by　the　different　molecular　packing.　This　study　not　only　allows　us　to　clearly　understand　the　relationship　between　the　molecular　structures　and　radioluminescence,　but　also　provides　a　guidance　to　rationally　design　new　organic　scintillators.　©　2021　Wiley-VCH　GmbH.