Next to carbon, boron probably has the richest chemistry with regard to catenation, which is the formation of chains of atoms of the same element. The number of "boranes" (hydrides of boron) that have been synthesized illustrates this rich chemistry. In general, these compounds have a formula of B_n H_n^2-. Replacement of two BH^- units with the isoelectronic CH moiety leads to the formation of carboranes. This results in neutral compounds with the general formula B_n-2C₂H_n, where n = 5 to 12.

Structurally, the boranes and carboranes fall into three classes of polyhedra. The closocompounds follow the regular polyhedra. The nido compounds are the regular polyhedra with one vertex missing. The arachno compounds have two missing vertices. Extensive rules have been developed for determining the structure of the resulting carborane from the electron count of the framework atoms.

The most common and important compounds are the two isomers of B₁₀C₂H₁₂. The carbon atoms are found either adjacent (called "1,2") or separated by a single boron (called "1,7"). These carboranes exhibit a rich chemistry as the hydrogen atoms on the carbons react readily with metallic lithium. The lithium atoms transfer two electrons to the carborane and the resulting dianion reacts with a number of electrophiles. The number of compounds that have been synthesized by this method is significant. The principle driving force for this research is the industrial application of carboranes in the synthesis of high molecular-weight polymers. Dual functionalization allows their incorporation into, for example, silicones where the carborane enhances the thermal stability of the polymer.

Carboranes have also been utilized in the synthesis of discrete metal ion compounds. Although not strictly speaking "organometallic", the resulting species bear a strong resemblance to the metallocenes in their chemistry and are isolobal (have the same number, symmetry properties, shape and approximate energies of their frontier orbitals) with the cyclopentadienyl radical. The chemistry of these compounds is still an area of active investigation.