**3. Conclusions**

In the copper/chloride compounds described here, the flexible bis-tetrazole organosulfur ligands BMTTM and BMTTE have proven to be able to adopt different coordinative modes to produce different coordination geometries (tetrahedral, octahedral and square-pyramidal) around the copper ions and different covalent dimensionality (from 0D to 2D) in the resulting crystalline solids. With BMTTM, all of the synthetic methods used (except the hydro/solvothermal method) led to the same 1D coordination polymer. However, with BMTTE, the softest methods led to a 2D coordination polymer and the reaction under hydrothermal conditions led to the reduction of copper(II) to copper(I) and the crystallization of a discrete tetramer.

The supramolecular organizations in these thermally stable compounds are mainly determined by C–H···X (X = Cl, N) interactions, with a significant role of the coordinated chloride and the uncoordinated nitrogen atom of the tretrazole as acceptors and of the methyl and methylene groups of ligands as donors. Other, less common interactions, such as Cl··· π (1), π··· π (2) and S··· π (3) contribute to the stabilization of the corresponding supramolecular networks, which achieve a very efficient packing. The Hirshfeld surface analysis corroborated the main geometrical observations about the crystal packing and highlight the importance of the methyl groups in establishing C–H··· X (X = Cl, N or S) interactions.
