Coordination polymerizations of para-substituted phenylallenes (2a-2e) were carried out by using [(pi-allyl)NiOCOCF3](2) (1) as an initiator. The polymerizations were found to proceed through a living mechanism to yield polymers exclusively composed of 2,3-polymerized units in high yields, where the resulting polymers have predictable molecular weights and narrow molecular weight distributions, From kinetic studies, the polymerization rate was found to increase with the electron-donating character of the para substituent in 2. The coordination polymerizations of alpha-methylphenylallene (2f) and gamma-methylphenylallene (2g) were also carried out to produce soluble polymers. In these cases, the methyl substituent on the allene moiety (especially at the gamma-position) was found to reduce the polymerizability. A plausible polymerization mechanism was also discussed based on the results obtained in the study.