Photodynamic therapy (PDT) is an innovative and promising method for treating tumors that has attracted significant interest but still faces several challenges, such as a lack of selectivity, deep penetration of light, and efficient ROS generation. To address these challenges, we optimized and synthesized a series of photosensitizers and successfully developed a heavy-atom-free near-infrared FUCL photosensitizer NFh-NMe-2. This photosensitizer can generate singlet oxygen (1O2) and induce cellular apoptosis under 808 nm light. For the safe ablation of microtumors in vivo, an activatable FUCL photosensitizer NFh-NTR was developed based on the overexpression of nitroreductase (NTR). NFh-NTR could be activated by NTR, leading to the release of the photosensitizer NFh-NMe-2, restoring the fluorescence signal, and effectively killing tumor cells under 808 nm light irradiation. This work opens new possibilities in the chemical design of an FUCL photosensitizer for cancer treatment.