Ab initio quantum chemical methods were used to study ground-state energies and geometrical configurations of boron and boron hydrogen chains. The ground-state energies of the boron chain were found to be comparable with those of boron clusters. The structure of chains can be obtained by unfolding the two rings of boron nanotubes. The ab initio ground-state energies of the dimerized (BH)_n chain were fitted into the SSH model, in order to determine the corresponding parameters for the ground-state energy. According to the SSH model, this dimerization induces a band gap of around 0.6 eV.