This mini-review provides recent progress in the synthesis of rare earth metal dialkyl complexes and their application as highly efficient and regio-/stereoselective catalysts in the coordination-insertion (co)polymerization of olefins such as styrene, isoprene, 1,3-cyclohexadiene, and ocimene. Through modifying the coordination atom, the ligand skeleton, and the substitutent on the skeleton of the chelating ligand, tuning the electron density and the steric environment around the rare earth metal center, the precise control of the activity and regio-/stereoselectivity of the (co) polymerization as well as the comonomer incorporation and sequence distribution of the resulting copolymers are achieved. (C) 2017 Wiley Periodicals, Inc.