Organic-inorganic　copper　halides　(OICHs)　are　attractive　due　to　their　outstanding　photophysical　properties,　low　toxicity　and　high　abundance.　However,　the　absence　of　the　high-energy　emissive　OICHs　significantly　hinders　the　full-spectrum　white　light　emitting　diode　(WLED)　for　high-quality　applications　and　the　preparation　of　large-area　films　still　faces　challenges.　Herein,　we　have　synthesized　a　novel　cyan　emissive　(C19H18P)2CuI3　by　lowering　the　inorganic　anion　skeletons　dimension　in　yellow　emissive　(C19H18P)2Cu4I6,　and　proposed　an　UV　curing　technology　to　fabricate　large-area　composite　films　(10*10　cm2),　which　is　one　of　the　largest　reported　films　based　on　OICHs.　The　structure　and　luminescent　properties　of　(C19H18P)2CuI3　could　transform　into　that　of　(C19H18P)2Cu4I6　under　methanol　treatment.　Notably,　the　PLQYs　of　(C19H18P)2CuI3　based　cyan　and　(C19H18P)2Cu4I6　based　yellow　composite　films　are　78.2%　and　96.1%,　respectively.　Moreover,　the　cyan　and　yellow　composite　films　exhibit　desirable　endurance　to　air,　whose　PLQYs　could　remain　94.12%　and　96.26%　of　its　initial　value　stored　in　air　for　45　days.　Remote　WLED　with　high　luminous　efficiency　of　74.44　lm　W−1　and　powders　based　cyan-gap　free　WLED　have　been　fabricated.　Additionally,　the　(C19H18P)2CuI3　and　(C19H18P)2Cu4I6　based　compounds　are　used　as　luminescent　pastes　for　encryption　applications,　and　the　two　composite　films　are　also　used　for　X-ray　detection　and　imaging.　©　2025　Elsevier　B.V.