  A crystalline form of LiBC is known which has been predicted to be
superconducting, with a Tc comparable to that of MgB_2. In both compounds,
superconductivity is enhanced by the presence of two electronic bands, one of
which is close to a dimensional crossover. Here, we take a quantum chemical
approach, and investigate the structural and electronic properties of small
clusters (LiBC)_n (n=1-4). With increasing cluster size, we find that several
properties of crystalline LiBC evolve naturally from the corresponding
properties of the clusters. In particular, one may recognize the origin of the
solid bilayered structure, typical of magnesium diboride, and the character of
the electronic sigma-band, arising from the overlap of the atomic orbitals in
the in-plane BC rings. Two aspects especially emphasized are (a) the HOMO-LUMO
gap as function of n and (b) the role of different spin multiplicity.
