Robust photosensitizers with strong red/NIR fluorescence, efficient reactive oxygen species (ROS) generation and high photostability are highly desired for photodynamic therapy (PDT). Herein, three novel red conjugated polyelectrolytes (CPEs) with tetraphenylethene and 2,1,3-benzothiadiazole on the main chains and triphenylphosphonium on the side chains are developed. These CPEs display apparent aggregation-induced emission feature and high fluorescence quantum yields in the aggregated state. They can target lysosome in HeLa cells for fluorescence bioimaging. By virtue of the good retention effect and high photostability, these CPEs show ultralong-term tracing performance of subcutaneous tumors, and the tumor site can still be visualized for 20 days after injection. Owing to their good biocompatibility and strong ROS generation ability, the image-guided PDT based on these CPEs can effectively inhibit the growth of subcutaneous tumor and significantly prolong the survival of tumor bearing mice. The H&E and IHC staining reveal that the PDT of these CPEs depress the proliferation of tumor cells, and promote apoptosis and necrosis process. These new CPEs may be employed both as fluorescent probes for in vitro and in vivo long-term tracing and as photosensitizers for image-guided PDT of tumors.

光动力疗法（PDT）非常需要具有强红色/ NIR荧光，有效的活性氧（ROS）生成和高光稳定性的强大光敏剂。在本文中，开发了三种新颖的红色共轭聚电解质（CPE），其主链为四苯基乙烯和2,1,3-苯并噻二唑，侧链为三苯基phosph。这些CPE在聚集状态下表现出明显的聚集诱导发射特征和高荧光量子产率。它们可以靶向HeLa细胞中的溶酶体进行荧光生物成像。由于具有良好的保留效果和较高的光稳定性，这些CPE表现出皮下肿瘤的超长期追踪性能，并且注射后20天仍可看到肿瘤部位。由于它们具有良好的生物相容性和强大的ROS生成能力，基于这些CPE的图像引导PDT可以有效抑制皮下肿瘤的生长，并显着延长荷瘤小鼠的生存期。H＆E和IHC染色表明，这些CPE的PDT抑制肿瘤细胞的增殖，并促进细胞凋亡和坏死过程。这些新的CPE可用作荧光探针体外和体内长期追踪以及作为光敏剂用于图像指导的肿瘤PDT。