AbstractRing‐opened polymers of racemic and optically active 5,5‐dimethylbicyclo[2.2.1]hept‐2‐ene (6) (5,5‐dimethylnorbornene), with cis double bond contents of 0–100%, were prepared using various Mo‐, W‐, Re‐, Os‐, Ru‐, and Ir‐based olefin metathesis catalysts. The13C NMR spectra of these polymers are interpreted in terms of TH, TT, HH, HT structures (T = tail, H = head, referring to the orientation of the methyl groups), also tt, tc, ct, cc structures (t = trans, c = cis double bonds), and m, r dyads (m = meso, r = racemic, referring to the relative configuration of adjacent cyclopentane rings in the chains). m/r splitting is observed for both the olefinic carbon (C3) and the adjacent ring carbon (C4) in the HH structures of the all‐trans polymer made from racemic monomer using RuCl3as catalyst. All‐cis polymers are fully syndiotactic while all‐trans polymers have 58% isotactic (m) and 42% syndiotactic (r) dyads. A consistent set of substitution parameters is derived, the effect of two methyl substituents on the13C chemical shifts being generally a little less than the sum of the effects o