As　an　important　interaction　among　organic　cations　containing　aromatic　rings,　the　pi-pi　stacking　interaction　is　a　crucial　factor　determining　the　crystal　structure　of　organic-inorganic　hybrid　metal　halides　(OIMHs).　However,　the　relationship　between　pi-pi　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　pi-pi　interaction　among　2,3　＇-bipyridinium　cations　in　23-Cd1-xZnxCl4　crystals.　When　x　＞　0.2,　pi-pi　interaction　among　organic　cations　occurs　and　enhances　as　the　Zn2+　content　increases.　The　tailoring　of　the　pi-pi　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　pi-pi　interaction,　while　the　orange　emission　enhances　and　finally　becomes　dominant　as　the　strength　of　pi-pi　interaction　increases.　The　pi-pi　interaction　promotes　the　energy　transfer　from　the　higher　energy　valley　to　the　lower　one　of　the　S-1　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　pi-pi　stacking　induced　tunable　light　emission　revealed　in　our　work　provides　new　guidance　for　the　design　of　luminescent　OIMHs.