Abstract: Glycidylated mono(alkyl aryl)phenols (styrenated phenols) or mixtures thereof are suitable for use as reactive diluents and co-reactants in the production of epoxy resins and have the structure of the general formula I shown hereinbelow wherein R1 and R2 independently of one another denote —H, C1-3-alkyl, C1-3-oxalkyl and glycidyl, but R1 and R2 are not simultaneously glycidyl, R3 is an optionally substituted styryl of the formula R4 is a hydrogen residue or methyl, and R5 and R6 are in each case a hydrogen residue, C1-3-alkyl, C1-2-oxalkyl.