Compounds having both s-triazine units and epoxide groups present are prepared by reacting an epoxide containing an isocyanate-reactive group with a triisocyanate corresponding to the formula: ##STR1## in which X is as defined herein. These reactants are used in quantities such that the equivalent ratio of isocyanate groups to isocyanate-reactive groups is maintained at less than or equal to 1 to 1. The compounds thus produced are particularly useful as reactive cross-linkers in the production of polyurethanes and polyepoxides.