Abstract: A method for chemically modifying an anionic metal complex, by obtaining from an anionic metal complex insoluble in a non-aqueous solvent and a clathrate compound a clathrate complex thereof with a counter cation of said metal complex, which is soluble in a non-aqueous solvent, and then reacting functional groups of the metal complex, which are not concerned with the coordination of said metal complex, with an organic reagent in the presence of a reaction assistant.The central metal from the chemically modified metal complex may then be removed.