Cr3+　doped　garnet-type　(A3B2C3O12)　near-infrared　(NIR)　phosphors　is　a　desirable　research　hotspot　due　to　their　prospective　night　vision,　bioimaging,　and　plant　growth　utilizations.　Meanwhile,　the　origin　of　multisite　broad　emission　is　yet　a　controversial　topic.　To　resolve　the　trouble,　verifying　accurately　the　multiple　Cr3+　occupancy　sites　is　a　key.　Furthermore,　it　is　an　urgent　need　for　improving　the　external　quantum　efficiency　and　luminescent　thermostability.　Herein,　in　Y3Sc2Al3O12　(YSAO),　advanced　electron　microscopy　technique　is　employed　to　directly　confirm　that　the　obtained　broadband　NIR　emission　originates　from　Cr3+　in　[ScO6]　octahedral　and　[YO8]　dodecahedral　sites.　The　optimal　YSAO:5%Cr3+　sample　exhibits　high　quantum　efficiency　(IQE/EQE = 74/31%)　and　near-zero　thermal　quenching　(97%@423　K　and　92%@473　K).　The　theoretical　calculations　and　experimental　proofs　reveal　that　YSAO　possesses　high　structural　rigidity　and　wide　bandgap,　which　is　responsible　for　the　extremely　thermostable　luminescence.　The　high-power　YSAO:5%Cr3+-converted　NIR　LED　device　shows　promising　multifunctional　applications.　This　work　not　only　provides　an　efficient　NIR　broadband　phosphor　with　near-zero　thermal　quenching,　but　also　provides　an　effective　determination　method　for　the　multiple　emitting　centers　of　phosphor　materials.　©　2024　Wiley-VCH　GmbH.