The molecule is dicarboxylate anion of (3Z)-phycocyanobilin. It is a dicarboxylic acid dianion and a linear tetrapyrrole anion. It is a conjugate base of a (3Z)-phycoerythrobilin.
3-[(2Z,5Z)-2-[[3-(2-carboxylatoethyl)-5-[(4-ethenyl-3-methyl-5-oxo-1,2-dihydropyrrol-2-yl)methyl]-4-methyl-1H-pyrrol-2-yl]methylidene]-5-[[(3Z)-3-ethylidene-4-methyl-5-oxopyrrol-2-yl]methylidene]-4-methylpyrrol-3-yl]propanoate