4,5,6,8,9‐Penta­chloro­pyrimido­[1,2‐a][1,8]­naphthyridin‐10‐one

The title compound, C₁₁H₂Cl₅N₃O, crystallizes in the monoclinic system with two mol­ecules in the asymmetric unit. The mol­ecules are chemically identical but have different structural parameters. In the three‐dimensional packing, the mol­ecules are arranged in dimers that are connected by slipped π–π stacking, and these dimers are connected to one another through several C—H·O and Cl·Cl interactions.