Photodynamic therapy (PDT) is a promising cancer treatment method that uses photosensitizing (PS) compounds to selectively destroy tumor cells using laser light. This review discusses the advantages of PDT, such as low invasiveness, minimal systemic toxicity, and low risk of complications. It focuses on chemical-synthesized photosensitizers, presenting three generations: the first based on porphyrins, the second on modified porphyrins, chlorins, 5-aminolevulinic acid (ALA), and its derivative hexyl aminolevulininate (HAL), and the third on nanotechnology to enhance selectivity. Current research trends include heavy-atom-free nonporphyrinoid photosensitizers, antibody-drug conjugates (ADCs), and photosensitizers with near-infrared (NIR) absorption peaks. The review highlights the development of PDT, considering advances in nanotechnology and biomedical engineering. The article covers the application of PDT in cancer therapy, the selection of synthetic photosensitizers, and the latest research findings, emphasizing the potential of new photosensitizers to overcome limitations in existing therapies.Photodynamic therapy (PDT) is a promising cancer treatment method that uses photosensitizing (PS) compounds to selectively destroy tumor cells using laser light. This review discusses the advantages of PDT, such as low invasiveness, minimal systemic toxicity, and low risk of complications. It focuses on chemical-synthesized photosensitizers, presenting three generations: the first based on porphyrins, the second on modified porphyrins, chlorins, 5-aminolevulinic acid (ALA), and its derivative hexyl aminolevulininate (HAL), and the third on nanotechnology to enhance selectivity. Current research trends include heavy-atom-free nonporphyrinoid photosensitizers, antibody-drug conjugates (ADCs), and photosensitizers with near-infrared (NIR) absorption peaks. The review highlights the development of PDT, considering advances in nanotechnology and biomedical engineering. The article covers the application of PDT in cancer therapy, the selection of synthetic photosensitizers, and the latest research findings, emphasizing the potential of new photosensitizers to overcome limitations in existing therapies.