The project aims to develop novel iridium(III) complexes for use in theranostics, combining the advantages of photodynamic therapy and diagnostics. Preliminary studies have shown that the newly synthesized photosensitive complexes, when activated, generate reactive oxygen species that precisely destroy cancer cells. In addition, they have high specificity of action and enable precise imaging of pathological changes in the body. The developed compounds will constitute an innovative group of candidates for the next generation of PDT-PDD drugs and will be distinguished by a number of advantages over those currently used, primarily: high water solubility, stability,selective accumulation in cancer cells, high tissue penetration capacity, precise intracellular action through mitochondrial processes, taking into account the peculiarities of cancer cells, by which they will show the ability to eliminate cancer cells with a variety of metabolic phenotype, very high efficiency of generating singlet oxygen and/or reactive oxygen/nitrogen species , suitable therapeutic excitation wavelengths and wavelengths for diagnostic applications in the so-called “biological window”. “biological window” (700-900 nm), in which light absorption and scattering by cellular components is minimal. Implementation of the project will make a significant contribution to the development of modern methods of cancer treatment, increasing the effectiveness of therapy and, thanks to innovative solutions , will enable a personalized approach and minimize the side effects of therapy.