This study aims to lower the high viscosity of epoxy resin for diverse applications and introduces novel reactive diluents synthesized from glycidyl methacrylate (GMA), butyl acrylate (BuA), and methyl methacrylate (MMA) via terpolymerization reaction using different GMA feed ratios with benzoyl peroxide (BPO) acting as a catalyst, BuA, and MMA. Therefore, in the presence of reactive diluents (RD), mechanical and physical tests were performed to determine epoxy resin's (E0) hardness, impact strength, tensile strength, and elongation at break. Fourier Transform Infrared Spectroscopy (FTIR) and thermogravimetric analysis (TGA) were used to characterize the generated reactive diluents, and hardener and epoxy resin were used in the ratio of 1:1, 1:0.5, and 1:0.3 respectively. According to the results, reactive diluents with 20% MMA successfully reduced the viscosity of epoxy resin from 8592 to 1900 mPa·s; thereby, no solvent is needed for coating application. All modified epoxy resin showed excellent adhesion and flexibility on the concrete and metal substrates at a hardener ratio of 1: 0.5. However, the acrylic monomers improved the corrosion and solvent resistance of the metal substrate, and 20% MMA content showed the best corrosion and solvent resistance. © 2025 Faculty of Engineering, Universitas Indonesia. All rights reserved.