A new phthalonitrile derivative bearing hexyloxy groups in the 3,6- positions and p-sulfonylphenoxy-and chloro groups in the 4 and 5- positions was synthesized. The new hexadeca-substituted zinc phthalocyanine was obtained by cyclotetramerisation of this phthalonitrile derivative in the presence of anhydrous zinc acetate under microwave heating. The aggregation behavior of the amphiphilic zinc phthalocyanine was studied in methanol and water. All novel compounds have been characterized by using elemental analysis, UV-Vis, FT-IR, H-1 NMR and MS spectroscopic data. The photosensitizing activity of this phthalocyanine dye was evaluated by application of 1,3-diphenylisobenzofuran as a singlet oxygen chemical quencher. In cell culture media the phthalocyanine showed a cytotoxic effect on HepG2 cells; a feature which encourages future in vivo studies. (C) 2013 Elsevier Ltd. All rights reserved.