Li1.72Na0.28Ge4O9 single crystal co-doped with Cr3+ (0.1 mol%) and Mn2+ (0.1 mol%) has been prepared by the Czochralski method. The electron paramagnetic resonance reveals presence of Cr3+ and Cr3+-Li+/Na+ pairs. Photoluminescence spectra show the sharp R1 and R2 emissions bands at 688-697 nm due to the E-2(g)->(4)A(2g) transition of Cr3+. They consist of three and two components, respectively. No emission from Mn2+ is observed because of energy transfer to the E-2(g) state of Cr3+. An effect of Mn2+ in the co-doped crystals is discussed. (C) 2014 Elsevier B.V. All rights reserved.