Using difunctional phenolic and amine compounds, a new polymer with benzoxazine groups in the main chain has been synthesized through the Mannich reaction of a phenol, formaldehyde, and an amine. H-1 and C-13 nuclear magnetic resonance spectroscopies, Fourier transform infrared spectroscopy, size exclusion chromatography, and elemental analysis are used to characterize the resulting polymer. Polymer with molecular weight of approximately 10,000 Da is obtained. The resultant polymer has a moderately broad polydispersity index. The thermal properties of the polymer have also been studied by differential scanning calorimetry and thermogravimetric analysis. (c) 2006 Elsevier Ltd. All rights reserved.