Metallocene/methylaluminoxane (MAO) and other single site catalysts for olefin polymerization have opened a new field of synthesis in polymer chemistry.1-3 Strained cyclic olefins such as cyclobutene, cyclopentene, norbornene (NB), and their substituted compounds can be used as monomers and comonomers in a wide variety of polymers.4 Much interest is focused on norbornene homo-and copolymers because of the easy availability of norbornene and the special properties of their polymers. Norbornene can be polymerized by ring opening metathesis polymerization (ROMP), giving elastomeric materials,5 or by double bond opening (addition polymerization). Homopolymerization of norbornene by double bond opening can be achieved by early and late transition metal catalysts, namely Ti, Zr, Hf,6-8 Ni,9,10 and Pd11-13 (Scheme 16.1).