As　an　important　interaction　among　organic　cations　containing　aromatic　rings,　the　π-π　stacking　interaction　is　a　crucial　factor　determining　the　crystal　structure　of　organic-inorganic　hybrid　metal　halides　(OIMHs).　However,　the　relationship　between　π-π　interaction　and　optical　properties　of　luminescent　OIMHs　is　yet　to　be　studied.　(C10H10N2)Cd1−xZnxCl4　(23-Cd1−xZnxCl4)　crystals　with　0D　structures　are　synthesized　by　using　optically　active　2,3′-bipyridine　as　the　organic　ligand.　When　x　≤　0.2,　there　is　no　π-π　interaction　among　2,3′-bipyridinium　cations　in　23-Cd1−xZnxCl4　crystals.　When　x　＞　0.2,　π-π　interaction　among　organic　cations　occurs　and　enhances　as　the　Zn2+　content　increases.　The　tailoring　of　the　π-π　interaction　endows　23-Cd1−xZnxCl4　with　tunable　light　emitting　properties,　resulting　in　a　broad　band　emission　involving　blue　and　orange　species.　The　blue　emission　dominates　when　there　is　no　π-π　interaction,　while　the　orange　emission　enhances　and　finally　becomes　dominant　as　the　strength　of　π-π　interaction　increases.　The　π-π　interaction　promotes　the　energy　transfer　from　the　higher　energy　valley　to　the　lower　one　of　the　S1　state　of　the　organic　cation,　resulting　in　the　enhancement　of　orange　emission.　Notably,　the　23-ZnCl　crystal　exhibits　a　photo-luminescence　quantum　yield　(PLQY)　of　32%.　This　is　the　highest　reported　value　to　date　among　the　Zn-based　OIMHs,　which　have　optical　emission　originating　from　the　organic　component.　The　mechanism　of　π-π　stacking　induced　tunable　light　emission　revealed　in　our　work　provides　new　guidance　for　the　design　of　luminescent　OIMHs.　©　2024　The　Royal　Society　of　Chemistry.