The recent development of high-quality backlighting systems, such as 8 K televisions or wide-color gamut mobile phones, have attracted much attention.[1–3] Narrow emission bandwidth hosphors should be developed to realize these high-quality systems. Among all colors, red photon generatorsare the most important materials to realize low color temperature and warm light in devices based on light emitting-diodes (LEDs). Traditional red phosphors, such as MAlSiN3 (M = Ca and Sr), are not suitable for attaining high spectral luminosity,because the broad emission of these materials makes a poor match with the eye sensitivity curve (emission has intensity beyond 650 nm).The sharp line emission of Mn4+ -activated fluoride phosphors are promising because of their zero aste photon ratios. The emission consists of narrow lines emission between 600–650 nm.Furthermore, the phosphor does not absorb the emission of the Y3Al5O12 :Ce3+(YAG) phosphor in an LED device. The luminescence of Mn4+ in solids is characterized by the zero-phonon line (ZPL) (2E!4A2) and associated sidebands (Stokes and anti-Stokes vibronic bands).The Mn4+ ZPL intensities in certain fluorides and oxidic phosphors have been reported.[9–11] The intensity of the ZPL,which corresponds to the emission without the participation of any phonons, is dependent on the host lattice. Compared with five phonon sidebands (PSs), ZPL is much more sensitive to the local oordinated environment. Thus, the ZPL has very low intensity in the most popular fluoridephosphors, such as K2SiF6:Mn4+ and K2TiF6:Mn4+.[12–14] Nevertheless, most of the studies on Mn4+doped fluoride phosphors have focused on the synthesis of new compounds or different synthesis methods