Abstract: A process for preparing metal-free phthalocyanine by reductive cyclization of phthalonitrile in the presence of an aliphatic alcohol, of a redox catalyst and of an inorganic base comprises effecting the cyclization in the presence of one or more phthalocyanine derivatives selected from the group consisting of phthalocyanine-sulfonic acids and -carboxylic acids and their alkali metal, ammonium and alkylarnozium salts, the amino-substituted and aminomethylated phthalocyanines and their reaction products with alkylating agents, sulfonic acids, sulfonyl chlorides and carbonyl chlorides, the imidomethylene- and amidomethylene-substituted phthalocyanines, the alkyl-, aryl- and cyano-substituted phthalocyanines, the hydroxyl- and alkoxy-substituted phthalocyanines and their reaction products with tetraalkyl- and tetraalkoxy-silanes and the halogenated phthalocyanines.