Metal-free tetrasulfophthalocyanine was synthesized by the reaction of triammonium salt of 4-sulfophalic acid with urea, using antimony powder as catalyst. The aggregation of this compound in aqueous and aqueous alcoholic solutions(MeOH, EtOH, ArOH) has been studied by electronic absorption spectra. The result shows that several factors such as the composition of the solvent, the acidity of solution, influence the extent of the aggregation. The dimerisation constant (Kd) of the titled compound in different solvents is reported.