The synthesis of efficient porphyrin-based photosensitizers with intense near-infrared (NIR) absorption is in high demand for photodynamic therapy (PDT) but remains a challenging task. Herein we show the construction of a type of isoquinoline-fused porphyrins and with an impressive NIR-absorbing capacity. In light of the extraordinary singlet oxygen generation capabilities of upon NIR irradiation, the representative nanoparticles () assembled show excellent tumoricidal behavior with good biocompatibility in the phototherapeutic window (650-850 nm).