Materials　that　emit　in　the　near-infrared　(NIR)　region　are　at　the　forefront　of　both　research　and　industry,　mainly　due　to　their　wide　applications　in　national　security,　nondestructive　bioimaging,　long-wave　communications,　and　photothermal　conversion　for　medical　care.　As　a　key　member　of　the　luminescent　materials　family,　metal　halide　perovskites　have　been　intensively　demonstrated　to　emit　light　in　ultraviolet　and　visible　regions.　However,　NIR-emitting　perovskites　suffer　from　severe　limitations,　such　as　low　photoluminescence　quantum　yield　and　poor　chemical/optical　stability,　thereby　preventing　them　from　practical　applications.　Herein,　the　synthesis　and　growth　of　Cs2MoCl6　and　Cs2WCl6　perovskite　single　crystals　with　ultrahigh　chemical　and　optical　resistance　to　heat,　moisture,　polar　solvents,　and　high-energy　radiation　is　reported.　Upon　ultraviolet　or　blue　excitation,　these　lead-free　single　crystals　emit　light　beyond　1100 nm,　the　longest　wavelength　ever　reported　for　perovskite　hosts.　Mechanistic　studies　indicate　that　self-trapped　excitons　are　responsible　for　the　NIR　emission.　The　authors　fabricate　optoelectronic　devices　using　these　single　crystals　and　demonstrate　their　broad　applications　in　noninvasive　palm　vein　imaging,　night　vision,　and　nondestructive　food　analysis.　These　results　may　stimulate　research　in　the　development　of　high-efficiency　NIR　perovskite　phosphors　for　fast,　accurate　biometric　identification　and　food　inspection.　©　2022　Wiley-VCH　GmbH.