Potassium 1-[2-(2-hydroxyethoxy)ethyl]piperazinedithiocarbamate (1) and bis{1-[2-(2-hydroxyethoxy)ethyl]piperazinedithiocarbamato} copper(II) (2) were prepared for the first time. The crystal structure of (2) was determined by single crystal X-ray diffraction analysis. (2) is a centrosymmetrical molecule with a CuS4 “core” plane. Theoretical studies for the similar compound bis[1-(2-hydroxyethyl)piperazinedithiocarbamato] copper(II) (3), (3)NO, (3)(NO)(H2O) and (3) (NO)2 were carried out by means of the SPARTAN’02 program.The interaction of the previously prepared [Cu{S2CN(CH2CH2OH)2}2] (4) with nitric oxide in aqueous solution at pH 7.4 and 20 °C was spectrophotometrically studied, and the experimental data were analysed by means of the SPEFO-LETAGROP program. The formation constants of the complexes (4)(NO) and (4)(NO)2 were determined.