The photochemical properties of Eu III and Tb III complexes with organic ligands under UV and visible light illumination are mainly related to their luminescence behavior. These complexes are known for their unique photophysical properties, which make them suitable for various applications, such as in luminescent materials, sensors, and bioimaging.1. Absorption: Eu III and Tb III ions have a low absorption coefficient in the UV and visible light region due to their electronic configuration f-f transitions . However, when they form complexes with organic ligands, the ligands can act as "antennas" that absorb light and transfer the energy to the metal ions, enhancing their absorption properties.2. Emission: Upon excitation, Eu III and Tb III complexes exhibit characteristic luminescence emissions. Eu III complexes typically show strong red emission around 610 nm due to the 5D0 7F2 transition, while Tb III complexes display green emission around 545 nm resulting from the 5D4 7F5 transition. The emission wavelengths can be fine-tuned by modifying the organic ligands or the coordination environment.3. Quantum yield: The luminescence quantum yield of Eu III and Tb III complexes depends on the efficiency of the energy transfer from the organic ligands to the metal ions and the radiative and non-radiative decay rates. By optimizing the ligand structure and the coordination environment, it is possible to achieve high quantum yields.4. Photostability: Eu III and Tb III complexes with organic ligands generally exhibit good photostability, which is essential for their practical applications. However, the photostability can be affected by factors such as the ligand structure, the coordination environment, and the presence of quenching species.5. Sensitivity to the environment: The luminescence properties of Eu III and Tb III complexes can be sensitive to the surrounding environment, such as temperature, pH, or the presence of specific analytes. This feature can be exploited for the development of luminescent sensors and probes.In summary, the photochemical properties of Eu III and Tb III complexes with organic ligands under UV and visible light illumination are mainly related to their luminescence behavior, which can be tuned by modifying the ligand structure and the coordination environment. These complexes have potential applications in various fields, including luminescent materials, sensors, and bioimaging.