We have synthesized CdS and Cd_0.7Mn_0.3S nanocrystals with diameters of about 4.5nm. These materials have been studied using photoluminescence spectroscopy with various excitation energies in the temperature range from 1.8 to 300K. We registered surface and defect states as well as two Mn²⁺ energy levels that correspond to Mn²⁺ ions in two different crystal environments. In addition, the resonant behavior of one Mn state excited by 514.5nm wavelength of laser light has been clearly observed in obtained spectra. We proposed the scheme of energy levels and transitions that explain obtained experimental results.