The optoelectronic properties of hexagonal boron-nitride and boron-nitride nanotubes (BNNTs) are investigated by using photoconductivity experiments, associated to photoluminescence excitation analysis. By this way, excitations related to the conduction band of hexagonal boron-nitride have been experimentally determined, as well as the free excitonic level. Multiwalled boron-nitride nanotubes have also been lead by using these methods and the first results suggest some hypotheses about the band gap energy and the nature of the various absorptions, which occur under an UV excitation. These experimental results are presented and discussed and some perspectives are finally suggested.