Methyl pyropheophorbide-a, one of the chlorophyll-a derivatives, was modified to chlorins possessing/lacking oxo groups at the peripheral 3 1 -, 8 1 -, and 13 1 -positions. Since the carbonyl groups were directly conjugated with the chlorin π-system in a molecule, such electron-withdrawing groups affected visible absorption and fluorescence emission spectra, emission efficiencies, and emission lifetimes as well as oxidation potentials of the semi-synthetic chlorophyll derivatives in a solution. The substitution effect was dependent on the connecting positions.