The present invention provides polymeric quaternary ammonium photoinitiators being co-polymers of photoinitiator monomers, as well as quaternary ammonium photoinitiator monomer being valuable intermediates in the preparation of such polymeric photoinitiators. Additionally, there is provided a polyacrylate obtained by radical polymerization of at least one acrylate monomer (Ac) in the presence of such polymeric photoinitiators. In the photoinitiator monomers and polymeric photoinitiators, a photoinitiator moiety and a quaternary ammonium are incorporated into the photoinitiator structure.