Confronted　with　the　imperatives　of　modern　technological　advancement,　the　development　of　phosphor　materials　capable　of　meeting　a　diverse　array　of　application　scenarios　has　become　an　urgent　challenge　in　both　scientific　research　and　industrial　fields.　Employing　the　double　perovskite　Ca2ScSbO6　as　a　matrix,　a　series　of　Dy3+-doped　and　Dy3+/Mn4+　co-doped　phosphors　have　been　successfully　engineered　and　synthesized　through　a　high-temperature　solid-state　reaction　approach.　The　structural　integration　and　successful　doping　of　Dy3+　and　Mn4+　ions　into　the　matrix　lattice　were　confirmed　by　Rietveld　structure　refinement　and　XPS　analyses.　The　prepared　Ca2ScSbO6:0.06Dy3+　phosphor　exhibits　superior　thermal　and　color　stability,　with　the　emission　intensity　retaining　84.2　%　of　its　initial　value　at　420　K,　and　a　minimal　chromaticity　shift　of　8.49　×　10−4.　Furthermore,　a　white　LED　device　integrated　with　the　Ca2ScSbO6:0.06Dy3+　phosphor　and　a　378　nm　chip　demonstrates　a　correlated　color　temperature　of　4538　K　and　CIE　color　coordinates　of　(0.3595,　0.3630),　effectively　emitting　bright　white　light.　Leveraging　the　distinct　thermal　quenching　behaviors　of　Dy3+　and　Mn4+　ions,　as　well　as　the　decay　lifetime　characteristics　of　Mn4+,　the　application　of　Ca2ScSbO6:Dy3+,Mn4+　phosphors　in　a　dual-mode　optical　temperature　sensing　has　been　investigated.　The　Ca2ScSbO6:0.06Dy3+,0.002Mn4+　sample　demonstrates　a　maximum　relative　sensitivity　(Sr)　of　1.288　%/K　(@503　K)　when　analyzed　by　the　fluorescence　intensity　ratio　(FIR)　technique　under　352　nm　excitation.　Furthermore,　the　Sr　value,　based　on　the　lifetime　model,　reaches　a　maximum　of　1.161　%/K　(@503　K).　These　findings　underscore　the　promising　potential　of　Ca2ScSbO6:Dy3+,Mn4+　phosphors　for　applications　in　both　indoor　lighting　and　multimodal　optical　temperature　measurement.　©　2025　Elsevier　Ltd　and　Techna　Group　S.r.l.