We report on syntheses, characterisation by nuclear magnetic resonance (NMR) spectroscopy, X‐ray diffraction (XRD) measurements, and density functional theory (DFT) calculations of electronic/molecular structure and NMR chemical shifts of complexes of Bi(III), having the molecular formulae: [Bi{S₂CN(C₂H₅)₂)}₃] (1), [Bi{S₂CN(C₂H₅)₂)}₂(C₁₂H₈N₂)NO₃)] (2), and [Bi₂{S₂CN(CH₂)₅}₆ H₂O] (3). The powder XRD patterns of complexes (1) and (2) resembled the corresponding calculated powder XRD patterns for previously reported single crystal structures. Single crystal XRD structure of complex (3), reported in this work, adopted an orthorhombic system with a space group Pbca with a=10.9956(3) Å, b=27.7733(8) Å, c=35.1229(10) Å and α=β=γ=90°. The experimental solid‐state ¹³C/¹⁵N NMR data of the complexes (1)‐(3) were in accord with their X‐ray single crystal structures. The unit cell of the complex (3) shows a weak supramolecular Bi S interaction leading to the formation of a non‐centrosymmetric binuclear molecule [Bi₂{S₂CN(CH₂)₅}₆ H₂O], which displays structural inequivalence in both ¹³C/¹⁵N NMR, and XRD data. Assignments of resonance lines in solid‐state ¹³C/¹⁵N NMR spectra of complexes (1)‐(3) were assisted by chemical shift calculations using periodic DFT methods. The findings of the present multidisciplinary approach will contribute in designing molecular models and further understanding of the structures and properties of (diamagnetic) metal complexes, including heavy metal ones.