Bismabenzene (C5H5Bi) is the parent representative of a group of organobismuth compounds that are related to benzene with a carbon atom replaced by a bismuth atom.

Bismabenzene itself has been synthesised but not isolated because it is too reactive, tending to instead dimerize in a Diels-Alder addition.

[1][2][3] An unstable derivative with 4-alkyl substituents was reported in 1982.

[4] A stable derivative, with two ortho tri(isopropyl)silyl substituents, was synthesized from aluminacyclohexadiene, bismuth trichloride, and DBU in 2016.

[1][5]