A new conjugate polymer was prepared by an efficient thiol-ene coupling of one carborane with a linear PEG chain (Mn = 2,000 g/mol) and each carborane was further labeled with a fluorescence rhodamine dye. Such a novel polymer can associate in water to form narrowly distributed spherical vesicles that was characterized using a range of methods, including laser light scattering, confocal laser scanning microscopy and TEM. The vesicular structure is potentially multi-functional in biomedical applications; namely, serving as a boron neutron capture therapy (BNCT) agent, a hydrophilic drug carrier, and a diagnostic imaging fluorescent probe. As expected, either cleaving the thiol-ene linked PEO chain by esterase or destroying carborane by neutron irradiation results in a dismantlement of such a vesicle structure to release its encapsulated drugs. Its potential biomedical applications have been in vitro and in vivo evaluated. Our preliminary results reveal that these small vesicles can be quickly taken up by cells and have an enhanced stability in blood stream so that their targeting to specific cancer cells becomes feasible.