A 2-to-2' 18-to-18' doubly linked Ni(ii) norcorrole dimer: an effectively conjugated antiaromatic dyad.

The synthesis and properties of a 2-to-2' 18-to-18' doubly linked Ni(II) norcorrole dimer are described, which adopts a highly planar structure, resulting in effective electronic interactions between the constituent norcorrole units. Nevertheless, each norcorrole unit exhibits substantial antiaromaticity, which stands in sharp contrast to stacked norcorrole dimers.