Three types of boron-rich compounds in unusual bonding situations are described: First, salts that contain closo-hydroborate anions and exhibit hydrogen and dihydrogen bonds and a strong ammonia network; second, boron-rich metal borides with an unexpected metal-metal bond stabilized by Peierls distortion; and third, nanoscale metal borides that bind selectively to certain heptapeptides identified by the phage display technique.