Hemipyocyanine (1-hydroxyphenazine) is a simple phenazine metabolite produced by several species of Pseudomonas and Streptomyces. Hemipyocyanine exhibits broad spectrum activity with weak antibacterial, antifungal and antiviral activity. In the search for novel actives, hemipyocyanine and related phenazines are important dereplication standards to eliminate leads due to high amounts of weakly potent actives. Hemipyocyanine plays an important role in the biocontrol of plant diseases by some Pseudomonas strains.