Lewis acids are very useful reagents in organic synthesis. The classical Lewis acids currently used include BF3 ·ΟEt2, ZnCl2, SnCl2, TiCl4 and many others. Nickel chloride can be also added to this list. NiCl2 is a mild Lewis acid that promotes a wide variety of organic transformations in aqueous medium or organic solvent and may be used either catalytically or stoichiometrically. NiCl2 was also used in a key step in the synthesis of bibenzopyran-4-ol, [1] tetrahydrodicranenone B [2] and Allopumiliotoxins. [3] NiCl2 is a selective reductive agent when used with hydrides such as LiAlH4 and NaBH4. In fact, the mixture of NiCl2 and NaBH4 is used to prepare nickel boride, [4] a reducing agent for many functional groups: azide, [5] nitrile, [6] NO bond, [7] alkene [8] and haloalkane. [9] NiCl2 was used in the regioselective rearrangement of dienols, [10] ring-opening of epoxide, [11] nickel(II)/chromium(II) chloride-mediated addition to aldehydes or ketones, [2] [3] Suzuki cross-coupling, [12] Biginelli reaction, [13] reductive Heck-like reactions, [14] nickel-catalyzed cross-coupling reaction of Grignard reagents [15] and homo-coupling reactions. [16]