Cryolite (Na3AlF6) was assumed to be a promising luminescent host for near-infrared photon emission with transition metal (TM)/rare earth (RE) ions as dopants. Micron cryolite samples were obtained through hydrothermal reaction, while nanocrystals were synthesized via solvothermal reaction. It is demonstrated that RE3+ ions having large radii cannot be doped into Na3AlF6 host lattice by replacing Al3+ sites that with smaller radius. TM ions(TM=Mn2+ , Ni2+, Cr3+, Fe3+) are successfully doped into Na3AlF6 with substitution of Al3+ sites, while the Cr3+ doped Na3AlF 6 exhibited broad efficient deep-red emission at ~720 nm. A systematic study of luminescence intensity versus Cr3+ concentration was explored to obtained the optimized cryolite phosphor. Energy decay dynamics was systematically analyzed on the basis of theoretical model and experimental data. Heat-treated micron phosphor and Na3AlF6:60mol%Cr 3+ Na3AlF6 nanoparticles were proved to have efficient luminescence, which create big chance for advanced red/far-red light-emitting diodes (LEDs) and specific application like bioimaging in vivo.