N-(p-Methoxybenzyl)-N-vinylacetamide (1), N-(3,3-diphenylpropyl)-N-vinylacetamide (2), and N-(3-phenylpropyl)-N-vinylacetamide (3) were synthesized as novel N-substituted-N-vinylacetamides to investigate polymerizabilities and stereochemistries on polymer main chains by introducing bulky substituents. Polymer was not obtained from I with a radical method; however, 2 and 3 gave rise to hexane-insoluble polymers during bulk polymerization with 14% and 84% yields, respectively, implying that alkyl spacers, were necessary between amide and phenyl groups. When 3 was polymerized with menthol at 0 degrees C, both H-1 NMR and C-13 NMR spectroscopies demonstrated sharper spectral patterns than those of poly(3) obtained at 60 degrees C. Since menthol coordinates with 3 at room temperature as shown by H-1 NMR spectroscopy, combinations of additive coordination and substituent bulkiness would be effective approaches to produce regulated polymer structure!;. Glass transition temperatures of poly(3)s also varied from 54 to 67 degrees C, depending on polymerization conditions and polymer structures.