The performance of several wave functions based on the molecular orbital, valence bond and non-paired spatial orbital methods has been examined for the bridge regions of diborane and the diborohydride ion. Electronic energy, overlap with more sophisticated wave functions and charge distribution are used. The non-paired spatial orbital method produces the most successful functions. The self-consistent field four-electron wave function for diborane reported by Hamilton has been improved and a full configuration-interaction, wave function for the bridge region of the diborohydride ion has been evaluated for comparison of simpler methods.