Reaction of excess sodium alkoxides with aromatic (non-enethiolisable) dithioesters followed by in situ alkylation offers a high-yield direct synthetic route to monothio-orthoesters. When applied to previously described monomers, polymers and copolymers containing dithioester groups, this method provides a direct access to the corresponding monomers, polymers and copolymers in which monothio-orthoesters are present. [(Methylthio) dimethoxymethyl]-4-vinyl benzene [obtained from methyl (4-vinyl benzene) dithiocarboxylate] undergoes convenient free radical homo- and co-polymerizations.