O-methyl-N-ethoxycarbonylthiocarbamate, CH₃CH₂OC(O)N(H)C(S)OCH₃ (I), and O-ethyl-N-ethoxycarbonylthiocarbamate, CH₃CH₂OC(O)N(H)C(S)OCH₂CH₃ (II), were prepared by the addition reaction between CH₃CH₂OC(O)NCS and the corresponding alcohols. Their structural and conformational properties were studied using low-temperature single crystal X-ray diffraction and vibrational spectroscopy assisted by quantum chemical calculations. Compound I crystallizes in the monoclinic space group P2₁/n with lattice parameters a = 4.2450(1), b = 18.4992(5), c = 9.8759(3) Å, β = 95.887(3)° and 4 molecules per unit cell (Z=4), and II in the triclinic space group PĪ with parameters a = 4.1771(8), b = 9.235(2), c = 11.804(2) Å and crystallographic angles α = 98.17(1), β = 98.62(1), γ = 102.29(2)°, and Z = 2. In the crystal,the conformation around the thiocarbamate group-N(H)C(S)O- is characterizedby a synperiplanar orientation of the C=S double with respect to the N-H single bond, while the methoxycarbonyl C=O double bond is in antiperiplanar orientation with respect to the N-H bond. Both species form dimers linked by NH•••S=C hydrogen bond, the N•••S non-bonding distance being 3.352(2) Å in compound I. Furthermore, ethoxycarbonylimidothiocarbonate species were obtained by the addition of methyl and n-butyl groups to the C=S double bond of I and II. Thus, species with formula CH₃CH₂OC(O)N=C (SCH₃)OCH₃ (III), CH₃CH₂OC(O)N=C(SCH₃)OCH₂CH₃ (IV), as well as the novel compounds CH₃CH₂OC(O)N=C(SC₄H₉)OCH₃ (V) and CH₃CH₂OC(O)N=C(SC₄H₉)OCH₂CH₃ (VI), were also prepared and fully characterized by spectroscopic methods.