A blue pigment produced by Penicillium herquei, previously well-studied but of unknown structure, has been isolated and demonstrated to be a phenalenone derivative. As isolated, the major blue pigment is a zinc complex of elemental formula C76H64O20N2Zn in which two anions of the dimeric phenalenone 2 act as the tridentate ligands. Compound 2 and the zinc complex have been identified previously as secondary metabolites of two other Ascomycetes. In addition, strong evidence was obtained for the presence in the CH2Cl2 extract of P. herquei of minor amounts of a novel compound, having a structure identical with that of the major blue pigment, but with nickel as the coordinating metal.