Low-dimensional　organic-inorganic　hybrid　manganese(II)　halides　are　emerging　as　a　highly　promising　class　of　candidate　materials　for　X-ray　imaging　due　to　their　excellent　radioluminescence　performance.　Here,　a　red-emitting　(Gua)2MnCl4　(Gua　=　guanidine,　CH6N3+)　single　crystal　scintillator　grown　by　a　simple　solution-processing　method　is　reported.　(Gua)2MnCl4　crystallizes　into　a　zero-dimensional　(0D)　crystal　structure　consisting　of　trimeric　[Mn3Cl12]6-　units.　It　has　a　high　PLQY　of　76%　and　a　large　Stokes　shift　of　125　nm.　(Gua)2MnCl4　flexible　scintillation　screen　demonstrates　a　decent　X-ray　detection　limit　of　145.3　nGyair　s-1　and　a　superior　imaging　resolution　of　8　lp　mm-1.　These　results　highlight　the　potential　of　low-dimensional　red-emitting　Mn-based　hybrids　for　X-ray　imaging　applications.　The　red-emitting　(Gua)2MnCl4　flexible　scintillation　screen　demonstrates　good　air　stability,　decent　X-ray　detection　limit,　low　afterglow,　high　radiation　resistance,　and　superior　imaging　spatial　resolution.　These　results　highlight　the　importance　of　developing　low-dimensional　Mn(II)　hybrid　halides　for　efficient　X-ray　detection　and　imaging　applications.　image