Six methacrylate monomers have been synthesized for use as reactive diluents in dental composites and evaluated to investigate the relationship between molecular structure and monomer reactivity. Four were synthesized by reactions of glycidylmethacrylate (GMA) with various acids, 2‐(2‐methoxyethoxy)acetic acid (1), 2‐(2‐(2‐methoxyethoxy)ethoxy)acetic acid (2), cyanoacetic acid (3), and benzoic acid