Alkyl　bromide　(R–Br)　was　employed　as　a　starting　compound　(precursor)　to　initiate　the　bulk　controlled　radical　polymerization　of　methyl　methacrylate　(MMA)　under　thermal　condition　(60　°C)　in　the　presence　of　tetra-n-octylammonium　iodide　(Oct4NI)　and　2,2′-azobisisoheptonitrile　(V65).　Alkyl　iodide　(R–I)　and　tetraoctylammonium　bromide　(Oct4NBr)　were　in　situ　generated　by　the　reaction　of　R–Br　with　Oct4NI　and　then　R–I　was　employed　as　an　initiating　dormant　species　for　the　polymerization.　Carbon-iodine　(C–I)　bonds　were　cleaved　and　radicals　were　generated　by　the　catalyst　of　Oct4NI　and　Oct4NBr.　The　chain　end　groups　of　the　obtained　polymers　contain　both　I　and　Br,　which　was　proved　by　the　results　of　1H　nuclear　magnetic　resonance　spectra,　and　elemental　analysis.　The　reversible　halogen　exchange　of　Br　with　I　at　the　polymer　chain　end　promotes　the　polymerization.　The　introducing　of　V65　not　only　increased　the　polymerization　speed,　but　also　ensured　high　monomer　conversion.　Low-polydispersity　(Mw/Mn　=　1.1–1.5)　polymers　were　obtained　with　high　conversions　(e.g.,　70–90%)　in　the　polymerizations　of　methyl　methacrylate,　styrene,　acrylonitrile,　and　functional　methacrylates.　The　attractive　feature　was　that　alkyl　bromide　was　able　to　initiate　the　controlled　radical　polymerization　of　methyl　methacrylate　under　thermal　condition　in　the　presence　of　organic　catalyst.　Besides,　this　new　system　presented　desirable　features　of　high　monomer　versatility　and　the　accessibility　to　a　wide　range　of　polymer　structural　designs　for　use　in　a　range　of　applications.　©　2020