Long-persistent phosphor is a kind of optical material where luminescence can last for several minutes to hours after stoppage of the excitation.In the past decade, phosphors with visible (400-680 nm) long-persistent phosphorescence (LPP)have been well developed.In contrast, the research on near-infrared (NIR, 680-2500 nm) LPP materials is far behind their visible counterparts, although there are growing demands recently for applications as taggants in nigh-vision surveillance and as optical probes in in vivo bio-imaging.In the present work, several Cr3+ doped phosphors (including SrGa12O19, Ca3Ga2Ge3O12 and transparent glass ceramics containing LiGa5O8 nanocrystals) with NIR LPP lasting for more than 2h are reported.Based on detailed analyses of the photoluminescence and thermoluminescence spectra, as well as the persistent decay behaviors of these Cr3+ doped samples, their NIR LPP mechanisms are systematically discussed.Impressively, Ln3+ (Ln=Nd, Dy, Ho, Er, Tm, Yb) doping is demonstrated to be an effective route to improve LPP performance of the Cr3+∶ Ca3Ga2Ge3O12 phosphor.