A difunctional 1,3-benzoxazine compound, 2,2＇-(3-phenyl-4-dihydro-1,3,2-benzoxazine)propane (B-a), derived from bisphenol-A, N-15-enriched aniline, and formaldehyde was synthesized and characterized using N-15-NMR and C-13-NMR spectroscopies. The observed resonances in the solid-state N-15- and C-13-NMR spectra showed good agreement with the calculated chemical shifts which are based on the chemical structure. The B-a samples were cured at 150 and 200 degrees C. The polymerization inspired peak intensity changes and line-width broadenings in the NMR spectra.