TiO2-xMgO: 0.1 at% Mn4+ (1 <= x <= 2) red phosphors are synthesized through a traditional high temperature solid-state reaction method. The excitation and emission spectra indicate that 700 nm and 660 nm red emission peaks are ascribed to Mn4+ ions doped in MgTiO3 and Mg2TiO4, respectively. The Ti4+ octahedron is connected in MgTiO3 by O2- ions of the octahedrons, while the Ti4+ octahedron is separated in Mg2TiO4 by Mg2+ tetrahedron and Mg2+ octahedron. This results that the quenching concentration is higher in Mg2TiO4 than in MgTiO3 leading the less luminous centers in MgTiO3. Detailed spectroscopic and crystal-field studies of the Mg2TiO4: Mn4+ and MgTiO3: Mn4+ is described in the present paper. (C) 2016 Elsevier Ltd. All rights reserved.