Crystallization of the copper(I) halides (CuX; X = Cl, Br, I) with N,N′-diphenylthiourea (‘dptu’ = (PhNH)2CS) in 1:2 ratio from acetonitrile solution in ambient conditions yields a mononuclear isomorphous series of complexes of the form [XCu(dptu)2]·H2O, an unusually complete array, with the central copper atoms in quasi-trigonal planar environments, as shown by single crystal X-ray studies, in turn providing a platform for comparative spectroscopic studies. Under anhydrous conditions, anhydrous compounds may be obtained, a full series again being accessible, but now of the binuclear form [(dptu)XCu(μ-S-dptu)2CuX(dptu)], the chloride being a bis(acetonitrile) solvate, the isomorphous bromide and iodide pair being unsolvated. A (solvated) sulfate salt is found to be of the form [Cu(dptu)2]2(SO4), providing a novel example of a copper(I) atom being (quasi-)linearly coordinated by the pair of unidentate (dptu) sulfur ligands, Cu–S 2.1770(5), 2.1811(5) Å, S–Cu–S 162.18(2)°. The ν(CuX) vibrational frequencies are assigned in the far-IR spectra of [XCu(dptu)2]·H2O (X = Cl, Br, I) at 274, 207, and 190 cm−1 respectively. The broadline static 65Cu NMR spectra of [Cl2Cu2(dptu)4]·2CH3CN and [X2Cu2(dptu)4] (X = Br, I) have been recorded at 9.4 and 7.05 T, and the spectra have been analysed to yield the 65Cu nuclear quadrupole coupling and chemical shift parameters. The 63,65Cu nuclear quadrupole resonance frequencies of [XCu(dptu)2]·H2O (X = Cl, Br, I) have also been measured, and the resulting 65Cu quadrupole coupling constants are ca. 4× those of the dimeric [X2Cu2(dptu)4] compounds.