Herein, we describe the synthesis and characterization of new ligands, N, and N,N-dipropyl-NЈ-(1-naphthoyl)thiourea (1b), and their complexes with copper, bis[N,N-diethyl-NЈ-(1-naphthoyl)thioureato]Cu II (2a) and bis[N,N-dipropyl-NЈ-(1-naphthoyl)thioureato]Cu II (2b). All four compounds (i.e., 1a, 1b, 2a, and 2b) were characterized by elemental analysis, 1 H NMR and 13 C NMR spectroscopy, and FTIR spectroscopy. The structures of compounds 1a, 1b, and 2b were determined by single-crystal X-ray diffraction analysis. Thermogravimetric analysis of 2a and 2b showed that both compounds decompose between [a]