The anodic oxidation of tetrafluoroborate anion yields the Lewis acid BF₃. If this reaction is carried out in an imidazolium ionic liquid, a quite stable system containing BF₃ is obtained, whose reactivity is similar to the one of BF₃·Et₂O, but less harmful. The two reagents’ stabilities were compared by computational analysis, strongly suggesting a higher stability for BF₃/BMIm-BF₄ system. The effect of substituents on the imidazolium ring and of the electrochemical configuration on BF₃ reactivity were studied in a model reaction, styrene oxide isomerization. The experimental conditions were defined for the selective formation of phenylacetaldehyde or of 2-benzyl-4-phenyl-1,3-dioxolane. Moreover, the formation of N-heterocyclic carbene-BF₃ adduct was confirmed when carrying out the electrolysis in an undivided cell. Electrogenerated BF₃/BMIm-BF₄ system demonstrated to be a valid alternative to commercial BF₃·Et₂O.