Copolymerization behavior of 5,6-benzo-2-methylene-1,3-dioxepane (BMDO) with styrene (SO is studied using benzyl bromide/CuBr/1,1,4,7,7-pentamethyldiethylenetriamine radical initiating system. Structural characterization of copolymers was done using 1D and 2D NMR techniques. The copolymer compositions were obtained from H-1 NMR spectroscopy. The reactivity ratios for the copolymerization of BMDO with St were determined using Kelen-Tudos method and was found to be r(BMDO) 1.08 and r(St) = 8.53. Degradation behavior of the copolymers is also reported.