The A 2 u X 2 g vibronic spectrum of 1 1 B 1 6 O 2 and its 1 0 B and 1 8 O isotopomers, produced by laser vaporization of boron in the presence of oxygen and trapped in solid neon, is studied through FT-absorption and laser induced fluorescence. The quantum yields of the laser induced fluorescence were found to exhibit a strong isotope dependence due to non-radiative relaxation. Frequency resolved emission spectra were measured in the visible and near-infrared region for four different isotopomers of BO 2 to obtain new information about the vibrational structure of the ground state.