Cyclic 1,2-diselenides are known to exhibit three σ-holes around the Se atoms—two in the prolongation of the Se–Se bond and one merging the two electron-depleted areas in the prolongation of the C–Se bonds. Among them, naphthalene peri-diselenides were recently isolated in their radical cation form with halometallates, affording 1:1 salts, where charge activation upon oxidation leads to strong Se•••Cl/Br chalcogen bond (ChB) interactions. Acenaphthene peri-diselenide (1) is shown here to be readily oxidized to its cation radical, showing various association modes of the 1^+• species in the solid state. When engaged in electrocrystallization experiments with (Bu₄N)(FeCl₄), acenaphthene peri-diselenide (1) afforded two salts of the radical cation, formulated as (1)₂(Fe₂Cl₆O) and (1)(FeCl₄), depending on the electrocrystallization conditions. In both salts, short and highly directional Se•••Cl chalcogen bond (ChB) interactions take place, simultaneously involving all three σ-holes surrounding the diselenide bridge, with the reduction ratio (relative to the van der Waals Se•••Cl contact distance of 1.90 + 1.75 = 3.65 Å) reduced to 0.89. In addition, while cation radicals in (1)₂(Fe₂Cl₆O) adopt head-to-tail alternated stacks without any intermolecular Se•••Se contacts, they organize in (1)FeCl₄ into twisted-cofacial dimers, with an intra-dimer Se•••Se contact as short as 3.197(2) Å, i.e., a reduction ratio of 0.84. Such structural organization is reminiscent of those observed in dithiadiazolyl/diselenadiazolyl radicals, which associate into dimers, most often in a cis-cofacial geometry. Here, the 1^+• radicals adopt either a head-to-tail (trans-cofacial) geometry (in the Fe₂Cl₆O²⁻ salt) or a distorted twisted-cofacial geometry (in the FeCl₄⁻ salt), further stabilized by the chelating FeCl₄⁻.