Gallium(III)-phthalocyanine chloride is primarily utilized in the field of photodynamic therapy (PDT) for cancer treatment. It acts as a photosensitizer, where it is administered to the patient and then activated by specific wavelengths of light. Upon activation, it generates reactive oxygen species that can destroy cancer cells selectively, minimizing damage to surrounding healthy tissues. Additionally, this compound is explored in the development of organic semiconductors due to its excellent light absorption and charge transport properties. It is also studied for use in optical data storage and as a component in solar cells, leveraging its ability to convert light into electrical energy efficiently.