Complex and multiband photoluminescence spectra for GB and HBN centers in single crystals of cubic boron nitride (cBN) were recorded in the wavelength ranges 385-400 nm and 365-395 nm and the nature of these centers was studied. The use of models involving resonance vibrations and strongly shifted configuration diagrams for the electronic ground state and excited state made it possible to associate formation of the GB-1 center with the presence of tungsten impurity in cBN. It was established that the HBN band in the 300-350 nm range of the cathodoluminescence spectra of cBN polycrystals, single crystals, and micropowders is associated with luminescence centers present in microinclusions of graphite-like boron nitride (hBN). The nature of the hBN band is tentatively interpreted within the model of recombination of donor and acceptor defects in hBN: respectively nitrogen vacancies and carbon atoms in positions substituting for nitrogen.Key words: cubic boron nitride, photoluminescence, cathodoluminescence, nature of optically active defects, luminescence center, spectrum with complex structure, resonance vibrations, configuration diagram.Introduction. Cubic boron nitride (cBN), as a wide-gap semiconductor, is a promising material for use in electronics and optoelectronics, detectors and devices suitable for operation under high radiation and temperature conditions and also in chemically aggressive media. Since the defect and impurity structure of cBN has not been well studied, it should be quite effective to analyze it by luminescence correlated with the macroscopic characteristics of the material, taking into account the indicated practical applications.From the standpoint of basic research on cBN, of course, direct analysis of the nature of the optical transitions at the luminescence centers in cBN is of interest, including comparison with its closest Group III-Group V analogs: diamond and gallium nitride.Thus in the luminescence spectra of gallium nitride, we observe a sufficient number of features of a type associated with donor-acceptor recombination or with recombination on free or bound excitons [1]. Of course, in the indicated cases, oppositely charged impurities or defects are present simultaneously in GaN which are introduced into the material by doping or are present in the material as intrinsic defects. Effective doping of diamond is difficult, and obtaining diamond with n-type conductivity is problematic. This is explained by the lack of luminescence centers of the above-indicated type in diamond [2] and formation of many defects in diamond such that electronic transitions in them are intracenter transitions.The number of luminescence centers in cBN that have been detected so far is small compared with diamond and GaN, and only isolated centers have been thoroughly studied. Based on the hypothetical nature of the optical transitions at these centers, the overall results of luminescent studies of cBN show considerable similarity to diamond. Thus in the luminescence spectra of cBN, the predominant bands...