• • PDI-P5·− radicals achieve a photothermal temperature of 90 °C under 0.20 W cm−2 simulated sunlight, demonstrating a high photothermal conversion efficiency suitable for low-power solar applications.
• • The radical anions exhibit broad NIR absorption and enhanced non-radiative transitions, attributed to ICT and PET mechanisms, which are critical for efficient photothermal conversion.
• • The PDI-P5·− radicals show excellent stability against oxygen, overcoming the typical instability of PDI radical anions, thus enabling practical applications in ambient conditions.
• • The material demonstrates superior multi-step photothermal anti-counterfeiting performance, indicating potential for advanced security features in anti-counterfeiting technologies.