The ground state geometries of the diradicals exhibit a clear trend with the increase in the atomic size of the chalcogen atom. There is an increase in the structural distortion of the diradicals as we progress down the group, with SH 2+•• being the least distorted and TeH 2+•• being highly distorted. To quantify the structural distortion, we have used the average dihedral angles (ϕ D ) between the pyrene coupler and benzene rings (Fig. ).