Here we discuss an efficient preparation of well-defined boron-functionalized styrene polymers. Atom transfer radical polymerization (ATRP) has been used to polymerize silylated styrene monomer to give poly (4-trimethylsilystyrene) (PSTMS), which was chain-extended with styrene to obtain well defined diblock copolymers (PSTMS-b-PS). After borylated with BBr3 to replace the trimethylsilyl groups, different methods were applied to obtain a series of new boron-containing diblock copolymers, which we anticipate to be valuable new hybrid materials with many potential applications. The amphiphilic properties of the resulting anionic (borate) and cationic (boronium) diblock copolymers lead to interesting self-assembly behavior in selective solvents. Different morphologies are observed depending on the nature of the solvent and the pH in the case of the related boronic acid polymer, PSBA-b-PS.