Porphyrazine III has been synthesized on a large scale (18.4 g), with minimal chromatographic purification by employing a novel one-pot, 3-step sequence. Two dinitrile precursors I and II, the latter of which consisted of a mixture of geometric isomers, were transformed, via the corresponding pyrroline diimines, into a mixture of III and the octa-Ar1-porphyrazine. Isolated macrocycle III was subsequently transformed into IV, a water-soluble seco-porphyrazine suitable for the labeling of biological vectors.