1-[Bicyclo[4.2.0]octa-1(6),2,4-trien-3-yl]-3-[bicyclo[4.2.0]octa-1(6),2,4-trien-3-yl­methyl]imidazolium hexa­fluoro­phos­phate

In the title compound, C20H19N2+·PF6−, the two benzocyclo­butene units are essentially planar and they form dihedral angles of 38.0 (2) and 72.7 (2)°, with the central imidazolium ring. In the crystal structure, weak C—H⋯π and π-–π stacking inter­actions [centroid–centroid distance = 3.742 (2) A] contribute to the stability of the crystal structure. The PF6− ion is disordered over two positions with site occupancies of 0.869 (9) and 0.131 (9).