The first sterically controlled oxidation of mesoionic selone using copper(II) salt was demonstrated. The present methodology gave access to a rare tetraselenide from dimerized diselenides through chalcogen bonding (ChB). Besides, a similar approach with sterically less crowded mesoionic triazole selone, 1-(2-mesitylene)-3-methyl-4-phenyltriazolin-5-selone, gave the classic diselenide salt. In the solid state, these new selenide salts demonstrate a unique structural aggregation with unusual bonding features such as Se···O and Se···F interactions. © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim