The combination of different types of π-conjugated anions into one structure can lead to multifunctional materials with intriguing properties. Herein, we successfully developed a new mixed anion compound, Ba₂(C₃N₃O₃)(CNO) (I), containing two types of π-conjugated groups, planar (C₃N₃O₃)³⁻ six-membered rings and linear (CNO)⁻ units, for the first time. The compound I exhibits the wide bandgap of 4.82 eV and high absorption coefficients in the wavelength range of 200–280 nm; this indicates that it is a potential optical detection material in the solar-blind region.