AbstractBy reactingN‐hydroxymethylphthalimide (5a) orN‐chloromethylphthalimide (5b) with an excess of phenol, a mixture of 2‐phthalimidomethylphenol (6) and 4‐phthalimidomethylphenol (7) was obtained. The ratio6/7was found to be 2:3 for the reaction with5aand 3:2 with5b, as determined by1H NMR at 250 MHz. The condensation of6with hexamethyleneteraamine (3) at the mole ratio6/3equal to 2 and 7,5 was performed at 190°C. The resulting resins (HPP) were compared to those prepared fromo‐cresol and3(HOC), and GPC of the resulting products was made. A higher thermal stability of the resins HPP was evidenced by thermogravimetric analysis. This improvement of the thermal stability was also observed for the condensation products of the ortho and para isomers6and7with phenol and formaldehyde, leading to modified novolacs FPP, although the amount of incorporated6and7was found to be less than the original amount in th