De Novo Design of Efficient NIR‐II‐Activated Heavy‐Atom‐Free Type‐I Photosensitizer for Anti‐Tumor Photoimmunotherapy

generation upon irradiation of 1064 nm light. In addition, the CTU3 NPs also exhibit a high photothermal conversion efficiency of 88.6%. In vitro and in vivo experiments show that CTU3 NPs have superior PDT and photothermal therapy (PTT) effects, which can further induce immunogenic cell death and activate immune cells in 4T1 tumor-bearing mice for combined PDT/PTT anti-tumor photoimmunotherapy against refractory tumors. This work presents a paradigm of de novo design of NIR-II light-activated type-I PS for combinational photoimmunotherapy of cancer.