AbstractThe discovery of highly efficient broadband near infrared (NIR) emission material is urgent and crucial for constructing NIR lighting sources and emerging applications. Herein, a series of NIR emission hexafluorides A2BMF6:Cr3+ (A = Na, K, Rb, Cs; B = Li, Na, K, Cs; M = Al, Ga, Sc, In) peaking at ≈733–801 nm with a full width at half maximum (FWHM) of ≈98–115 nm are synthesized by a general ammonium salt assisted synthesis strategy. Benefiting from the pre‐ammoniation of the trivalent metal sources, the Cr3+ can be more efficiently doped into the A2BMF6 and simultaneously prevent the generation of the competitive phase. Particularly, Na3ScF6:Cr3+ (λem = 774 nm, FWHM ≈ 108 nm) with optimal Cr3+‐doping concentration of 35.96% shows a high internal quantum efficiency of 91.5% and an external quantum efficiency of ≈40.82%. A lighting emitting diode (LED) device with a NIR output power of ≈291.05 mW at 100 mA driven current and high photoelectric conversion efficiency of 20.94% is fabricated. The general synthesis strategy opens up new avenues for the exploration of Cr3+‐doped high efficiency phosphors, and the as‐obtained record NIR output power demonstrates for NIR LED lighting sources applications.