Three new bisglycidyl monomers; 1,4-bis((2-hydroxy-3-methacryloxypropoxy) methyl)benzene (MB-Phe-OH), 1,4-bis(2-hydroxy-3-methacryloxypropoxy)2-cis-butene (MB-Cis-OH), and 1,7-bis(2-hydroxy-3-methacryloxypropoxy)heptane (MB-1,7-OH); were synthesized and used as Bis-GMA/TEGDMA (bisphenolglycidyl methacrylate/triethylene glycol dimethacrylate) composite resin additives. Flexural properties and double bond conversion of the dental resins composed of silanizated inorganic filler and organic matrices containing new monomers were evaluated. The composite resins formulated, using the monomers MB-Cis-OH and MB-1,7-OH, have mechanical properties and double bond conversion comparable with those of Bis-GMA/TEGDMA composite resin used as control. The composite containing the new monomer MB-Phe-OH has better flexural properties (flexural strength 65.01 MPa and flexural modulus 5675.91 MPa) than the control composite resin (flexural strength 52.85 MPa and flexural modulus 4879.72 MPa); this could be attributed to the molecular structure of the monomer and its high double bond conversion level of 74.19%. The new bisglycidyl methacrylate monomer MB-Phe-OH could be potentially useful in the development of new organic matrices for dental composite resins with high double bond conversion and enhanced mechanical properties. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40971.