In the past few years, red to near-infrared persistent phosphors activated by transition metals (Cr3+ or Mn2+) received much attention. The research was triggered by a recently proposed in vivo imaging application and it may show more significance in the future. In this review, we try to make a full list of known Cr3+ or Mn2+-activated compounds showing red to near-infrared persistent luminescence, which may be useful for further exploration of new compounds. We also notice that radiance (in units of W sr-1 m-2) is even more suitable than luminance (in units of cd m-2) to quantify the brightness of red to near-infrared persistent phosphors for the in vivo imaging application. Finally, we discuss the mechanism of the persistent luminescence by taking an example of Cr3+-activated Zn0.98(Ga1-xAlx)2O3.98 persistent phosphors. © 2014 Elsevier B.V. All rights reserved.