The results of CuGa3Se5 and CuGa5Se8 semiconductors characterization by photoluminescence (PL) and optical second harmonic generation (SHG) in reflection are reported. Both bulk single-crystals, belonging to the so called “ordered vacancies compounds” family [1], were grown by the Bridgman method. Their compositions were determined by means of the Energy Dispersive X-ray Microanalysis. The SHG investigation of both semiconductors were performed in a “reflection” geometry because of the strong absorption of the blue-green radiation in the samples, using a femto-second Ti-sapphire laser for excitation (λω=780nm, ћω=1.59eV). The natural cleavage surfaces of samples were used as “reflecting” planes. The intensity of the SH signal (λ2ω=390nm) was measured for (р-in, р-out), (p-in, s-out), (s-in, p-out) and (s-in, s-out) polarizations. The steady-state PL measurements were carried out in the spectral range ћωPL=1.2–1.9eV at T=8-200K under optical excitation with λex=532nm. For both compounds the measured azimuthal dependencies of SH signal are qualitatively similar, with 2:3 ratio of the amplitudes for CuGa5Se8 and CuGa3Se5 samples, respectively. The curves obtained were used for determination of point group symmetry of both samples as well as for the identification of reflecting planes orientation with respect to crystallographic axes. For these purposes the fitting procedure of measured dependencies to calculated ones was used. Taking into account the strong optical absorption of the SH signal generated in samples the theoretical model was developed for numerical simulations of SHG-response. This model includes several adjustable parameters, such as Euler’s angles, determining orientation of reflecting plane and the independent components of the nonlinear susceptibility tensor. The excellent fit was achieved for the 42m tetragonal point group and the (112) reflecting plane for both crystals. The bigger intensity of the SH signal for CuGa3Se5 in comparison with CuGa5Se8 can be explained by the fact that band gap value of the 1-st compound is closer to the excitation photons energy [2, 3]. The quasi-resonant conditions are provided by the conduction and valence bands density state tails inherent to these types of semiconductors. These tails are manifested in the PL spectra of the investigated samples as well. The asymmetric shape of the PL broad bands with maxima at ~1.7eV (T=8K) and the half width ~0.15eV, the temperature evolution of the spectra and the relatively fast temperature quenching of the integral emission intensity are quite similar for both semiconductors. The radiative and radiativeless recombination processes are discussed regarding to PL properties.