Harnessing a bis(selenomethyl)tetrathiafulvalene (TTF) derivative as a donor, conducting charge transfer (CT) salts are realized thanks to original packing structures supported by chalcogen bonding (ChB) interactions. Specifically, reaction of EDT-TTF(SeMe)(2) (EDT = ethylenedithio) with an acceptor, 2,5-difluoro-7,7,8,8-tetracyanoquinodimethane (F(2)TCNQ), afforded two polymorphs of 1 : 1 CT salts, alpha- and beta-[EDT-TTF(SeMe)(2)](F(2)TCNQ). The donor and the acceptor molecules in both polymorphs organize into segregated and uniform stacks. Based on the structure, the alpha-salt shows a quasi-complete CT while the beta-salt shows a partial CT with rho similar to +/- 0.8. The oxidation of TTF activates the sigma-hole on Se atoms to be engaged in highly linear ChB interactions with the N atoms on F(2)TCNQ. The formation of directional ChB interactions resulted in original packing structures of the donor and the acceptor stacks that are distinct between alpha- and beta-salts. In particular, the ChB motif observed in the beta-salt allows F(2)TCNQ molecules within the stack to be closer than those in the alpha-salt. Consequently, the alpha-salt is a semi-conductor, while the beta-salt shows metallic behaviour with a two-step metal-to-insulator (MI) transition. Moreover, the observed MI transition temperature in the beta-salt (180 K) is substantially higher than that in other known CT salts, likely owing to the 3D coupling of the modulation in different chains brought about by the -SeMe substituents.