Preparation of graft and branched polymers via photo-induced radical polymerization and photo-induced self-condensing vinyl polymerization (SCVP) routes, respectively, was studied. Precursor random co-polymers of styrene (St) and 2-(dimethylamino)ethyl methacrylate (DAEMA) were obtained via thermal polymerization initiated by azoisobutyronitrile, (AIBN) and used as macromolecular co-initiators in photo-induced grafting experiments. Successful grafting was achieved, while cross-linking also occurred to some extent. The resulting graft co-polymers were characterized by H-1-NMR and GPC measurements. The synthesis of branched polymers was carried out by the use of DAEMA as an inimer in photoinduced SCVP, in which irradiations were performed in a photoreactor emitting light with a wavelength of 350 nm. Surface morphologies of branched and linear polymers were examined by atomic force microscopy (AFM) and compared.