Luminescent　materials　with　tunable　emission　wavelengths/colors　hold　great　potential　for　smart　response　devices,　data　security,　sensors,　and　so　on.　However,　development　of　stimuli-responsive　luminescent　materials　with　traditional　organic　or　inorganic　luminophores　remains　challenging　due　to　their　lack　of　tunability.　Herein,　we　report　the　tunable　luminescence　and　ratiometric　temperature　sensing　applications　with　a　europium-organic　cage　(Eu4L4)　featuring　concentration-dependent　hierarchical　self-assembly　behavior.　Notably,　white　light　emission　was　achieved　by　adjusting　the　equilibrium　ratio　between　the　red-emissive　cage　monomer　and　cyan-emissive　cage　aggregate.　Taking　advantage　of　the　dual　emissive　nature　of　the　system,　ratiometric　luminescent　temperature　sensing　has　also　been　achieved,　exhibiting　a　sensitivity　of　2.04%　and　linear　correlation　coefficient　of　0.997　from　250　to　320　K.　©　The　Author(s)　2025.