See DOI: 10.1039/cXCP00000x/ tween p-orbitals on the perpendicular carbon termini. Recently, we demonstrated that this helical π-mixing also appears in spiroconjugated molecules. Shown in Figure , spiropentadiene belongs to the D 2d point group. Again, the rotation symmetry causes the frontier π-MOs to mix and form helical orbitals that span the full length of the molecule. The experimental implications of this electrohelicity effect remain limited because both helicities are present simultaneously. Consequently, this helical π-conjugation cancels out when the MOs are equally occupied in neutral closed-shell molecules.