Heat curable mixtures comprising(a) 5 to 95% by weight of at least one aromatic dicyanate or polycyanate compound or a prepolymer thereof,(b) 95 to 5% by weight of at least one compound of formula I or II ##STR1## or of a prepolymer of a compound of formula I or II, (c) 0 to 50% by weight, based on the sum of (a)+(b), of at least one compound of formula III ##STR2## (d) 0.1 to 50% by weight, based on the sum of (a)+(b), of at least one thermoplastic having a glass transition temperature of at least 120.degree. C., in which formulae aboveR.sub.1, R.sub.2 and R.sub.3 are each independently of one another a hydrogen atom or methyl,n is 1 or 2 and m is 2 or 3,R is hydrogen or an aliphatic, cycloaliphatic or aromatic radical, R' is an aliphatic radical, m- or p-phenylene or m- or p-phenyleneoxy, and R" is an organic radical or valency m containing 2 to 30 carbon atoms, are suitable for the production of mouldings such as prepregs or composites, coatings and bonds.