Homopolymers of 4-acryloyloxybenzoin methyl ether (ABME) and 4-acryloyloxy-alpha-methylbenzoin methyl ether (AMBE) [poly(ABME) and poly(AMBE)] as well as copolymers of AMBE with (-)-menthyl acrylate (MtA) and with different N,N-dialkylaminoethyl acrylates have been employed in the photoinitiated polymerization and crosslinking of a standard acrylic formulation for u.v. clear curable coatings. The photoinitiation activity of the above systems, detected by microwave dielectrometry, has been compared with that found for the corresponding low molecular weight structural models. The results clearly indicate that high and low molecular weight photoinitiators promote u.v. curing at a similar rate; however, a significant decrease of the induction period and hence an improved overall activity is found for the polymeric systems. An interpretation of the experimental findings, related to the behaviour of previously reported polymeric photoinitiators based on the benzoin methyl ether moiety, is also reported.