Pioneered by Sir R. Patrick Linstead as an extension of his work on phthalocyanines,[1] porphyrazines differ from porphyrins in that they contain -meso nitrogen atoms, rather than carbon atoms, and differ from phthalocyanines in that their β-pyrrole positions are open for substitution.

These differences confer physical properties that are distinct from both porphyrins and phthalocyanines.

[3] Cross-cyclization with phthalonitrile or diiminoisoindole derivatives is possible introducing a flexibile synthetic route that has led to the synthesis of porphyrazines with peripheral heterocyclic rings,[4] heteroatom substituents (S, O, N),[5] peripherally bound metal atoms,[6] and mixed -benzo porphyrazine systems.

[7] Porphyrazines are most well known for their intense electronic absorption throughout the UV, visible, and NIR spectral regions.

[7][9] Porphyrazines exhibit fluorescence from the first excited singlet state (S1 → S0)[10] at visible and NIR wavelengths which is typical of tetrapyrrole macrocycles.