Prussian blue (PB) has been used as a photothermal conversion agent to generate heat to induce localized damage "to tumor. However, its therapeutic efficiency is far from satisfactory. One of the major obstacles is that the maximum NIR absorption peak of PB within 690-720 nm cannot be optimized near the wavelength of the laser to enhance its therapeutic efficiency. Herein, we report that the integration of Gd3+ into PB nanocrystals (GPB NCs) enables PB with tunable localized surface plasmon resonances (LSPRs) from 710 to 910 nm, achieving the maximum NIR peak near the wavelength of the laser. Concurrently, the efficiency of dual-mode imaging including photo acoustic imaging and magnetic resonance imaging has been greatly improved. These enhancements in dual-mode imaging and photo thermal therapy enable PB with low nanomaterial dose and laser flux. Additionally, it is found that GPB NCs show the capability of not only acting as a chemical probe with tunable sensitivity but also scavenging reactive functional ions into a photothermal conversion agent is an efficient strategy to enchanting tumor theranostic efficiency. oxygen species. The integration of improve the synergy of nanoagent,