Structures and energies for BLin (n = 1-3) are investigated with various basis sets and with different levels of theory, including single reference-and multireference-based correlated methods up to QCISD(T)/6-311+G(3df)/MP2(full)/6-311 +G(d), MCQDPT2/6-311+G(2df)//CASSCF/6-31C(d), G2, and G2(MP2) theory. BLi ((3) Pi(g)), BLi2 (B-2(2)), and BLi3 (C-2v) are global minima with respective atomization energies of similar to 26, 55, and 95 kcal/mol. Their structures are not strongly influenced by the size of the basis set nor by the method of electron correlation employed. Energetics for low-lying excited states of BLi and BLi2 were determined. The dissociation energies obtained with B3LYP/6-31G(d) theory are in excellent agreement with those obtained with the highest levels of theory.