Generation of singlet oxygen upon excitation of oxygen molecules by infrared diode lasers has been studied in organic media (carbon tetrachloride and acetone) saturated by air under normal pressure and temperature. A new approach to analysis of the experimental data has been developed taking into account a degree of overlapping of the spectral bands of oxygen and laser radiation. Optical density, molar absorption coefficient and the cross section of light absorption were determined for the main absorption maxima of O2 at 765 and 1273 nm. The results are compared with the data of previous studies. A significance of the obtained results for elucidation of photophysics and photochemistry of oxygen molecules and investigation of biological action of laser radiation is discussed.