© 2020, Turkish Chemical Society. All rights reserved.A novel tetrasubstituted metal-free phthalocyanine bearing phthalonitrile groups on the peripheral positions was synthesized accidentally by the cyclotetramerization reaction of the 4,4’-(1,3phenylenebis(oxy))diphthalonitrile. For photodynamic therapy (PDT) application, photophysical properties including fluorescence quantum yield (ΦF), fluorescence lifetime (τF), triplet state lifetime (τT), and triplet quantum yield (ΦT) and photochemical properties including singlet oxygen quantum yield (ΦD) and photodegradation quantum yield (Φd) as well as magnetic circular dichroism (MCD) properties were described. The ΦT of the phthalocyanine was 0.81. The obtained lifetime (τT) was 40 μs for metal-free Pc.