In the structure of the title salt, [Co(C6H6N2)2(H2O)2](BF4)2, the CoII atom is located on an inversion centre. The transition metal is in a slightly distorted octahedral coordination environment, defined by the cyano N atoms of four hex-3-enedinitrile ligands in equatorial positions and the O atoms of two water molecules in axial positions. The bridging mode of the hex-3-enedinitrile ligands leads to the formation of cationic chains extending parallel to [110]. The BF4- counter-anion is disordered over two sets of sites [occupancy ratio = 0.512 (19):0.489 (19)]. It is located in the voids between the cationic chains and is connected to the aqua ligands of the latter through O-H⋯F hydrogen bonds. One methylene H atom of the hex-3-enedinitrile ligand forms another and weak C-H⋯O hydrogen bond with a water O atom of a neighbouring chain, thus consolidating the three-dimensional network structure.
