Unique nanosized closomers of high boron content that may exhibit potential as boron neutron capture therapy target species have been synthesized. The design of these boron-rich nanospheres is based in part on previous work involving dodeca(carboranyl)-substituted closomers [Thomas, J.; Hawthorne, M. F. Chem. Commun. 2001, 1884-1885]. Coupling of ortho-carborane moieties through ester and ether linkages to the rigid [closo-B-12(OH)(12)](2-) scaffold resulted in the development of a 12(12)-closomer-ester derivative, dodeca[6-(1,2-dicarba-closo-dodecaboran-1-yl)hexanoate]-closo-dodecabora te (2-), 6, and 12(12)-closomer-ether derivatives, dodeca[6-(2-methyl-1,2-dicarbanido-dodecaboran-1-yl)hexyl]-closo-dodecab orane (14-), 14, and dodeca[6-(7,8-dicarba-nido-dodecaboran-7-yl)hexyl]closo-dodecaborane (14-), 15. These closomers were investigated by UV-visible spectroscopy and cyclic voltammetry. Additionally, a deboronation method employing NaCN as the nucleophilic reagent was utilized to obtain sodium salts of the ether-linked nido-closomer polyanions, which were purified using a newly developed size-exclusion high pressure liquid chromatography method.