AbstractAnti‐counterfeiting and encryption are key technologies for information transmission in modern society. However, most optical materials offer only a single fixed response mode, limiting their security level in advanced anti‐counterfeiting applications. Exploring efficient and tunable long persistent luminescent (LPL) phosphors is urgently demanded and highly meaningful. In this work, a dual‐site occupancy strategy is innovatively reported via Li+ doped NaGaO2: Cu2+ (NGO: Cu2+/Li+) phosphors for enhancing LPL properties. To be specific, Cu2+ initially occupies both Na and Ga sites in NaGaO2, producing orange–yellow LPL at 585 nm and near‐infrared (NIR) emission at 712 nm, respectively. Furthermore, the introduction of Li+ will occupy the Na+ sites, attenuating the NIR emission and increasing the defect density of the oxygen‐deficient states, which results in enhanced LPL intensity and prolonged afterglow time. Significantly, the obtained NGO:Cu2+/Li+ exhibits multi‐emission modes with dynamic change of LPL time (10–20 min). More importantly, the NGO: Cu2+/Li+ has great potential applications in multi‐level information storage and encryption.