Organic room-temperature phosphorescent (RTP) materials have wide-ranging applications in anticounterfeiting, biodiagnostics, and optoelectronic devices due to their unique properties. However, it remains a challenge to give organic RTP materials dynamic tunability to satisfy the demands of various advanced applications. Herein, we propose an effective strategy to precisely modulate phosphorescent performance by incorporating dynamic metal-ligand coordination within a host-guest doped system. The organic phosphors of bipyridine derivatives with excellent coordination properties were doped into a small-molecule host matrix. Halide salts were doped in the host-guest system effectively tuning the phosphorescent performance, including efficiency and lifetime, through dynamic metal-ligand coordination. Notably, leveraging the reversible feature of the metal-ligand coordination, multilevel information encryption, including thermal development and time-resolved applications with high reversibility, is successfully demonstrated. The work demonstrates that dynamic metal-ligand coordination could serve as an effective method for developing efficient RTP materials with precisely tunable properties.