Transition metal complexes containing a planar three-carbon ligand, the π-allyl group was first described in 1958 with the discovery of (π-1-methylallyl)cobalt tricarbonyl. After this discovery, many other syntheses followed. This chapter deals with synthetic organic applications of pi-allylnickel complexes. At this time, the study of this subject is in its infancy. The unifying aspect of π-allylnickel chemistry is the ability of the allyl ligand to form new carbon-carbon bonds.