Abstract: A process for preparing metal-free phthalocyanines which can carry up to 16 halogen atoms, cyano groups, carboxyl groups, sulfo groups, C.sub.1 -C.sub.18 -alkyl groups and/or aryl radicals as substituents by reductive cyclization of ortho-phthalodinitrile substituted ortho-phthalodinitriles or mixtures thereof comprises effecting the cyclization in C.sub.2 -C.sub.4 -alkylene monoglycols, oligoglycols or polyglycols, their mono-C.sub.1 -C.sub.4 -alkyl or -aryl ethers or their mixtures in the presence of an aromatic compound of the formula I ##STR1## where the substituents X can be identical or different and each denotes hydroxyl, mercapto, amino or C.sub.1 -C.sub.6 -alkylamino, the substituents Y can likewise be identical or different and each denotes halogen, C.sub.1 -C.sub.6 -alkyl, C.sub.1 -C.sub.6 -alkoxy or C.sub.1 -C.sub.6 -alkoxycarbonyl, m is from 1 to 4 and n is from 0 to 5, subject to the proviso that m+n .ltoreq.