The diacrylate reactive diluent was synthesized by reacting glycidyl methacrylate, piperazine, and cyclic ethylene chlorophosphate. The synthesized reactive diluent was utilized to formulate UV-curable wood coating. The weight fractions of reactive diluent were varied from 0 to 25% in coating formulation with constant photoinitiator concentration. The molecular structure of reactive flame retardant was evaluated by FTIR, mass spectroscopy, 31PNMR, and 1HNMR spectral analysis. The flame retardant behaviors of the cured film were evaluated from limiting oxygen index and UL-94 vertical burning test. Thermal stability was estimated from thermogravimetric analysis and differential scanning calorimetry. The effects of varying concentrations of reactive diluent on the viscosity of the formulation along with optical, mechanical, and chemical resistance properties of coatings were evaluated. The gel content, water absorption behavior, and stain resistance of coatings were also studied.