Cobalt(III) complexes have been found to possess both antiviral and antibacterial activities. Recently, we showed that compounds based on hexaammine cobalt(III) trichloride and 1,10-phenanthroline can be applied in various chemical and biotechnological processes as an inhibitor of the development of bacterial cancer in plants [1]. This study investigates the role of 3-pyridine sulfonic acid in the structure formation of a new Co(III) complex focusing on multicomponent mononuclear compound with potential biological activity. A new Co(III)-containing compound, [Co(NH3)6]Cl(pys)2∙2MeCN (1), was obtained from the reaction of [Co(NH3)6]Cl3 with 3-pyridine sulfonic acid (Hpys) in the presence of triethanolamine in MeOH/MeCN (1:1) mixture. The single crystal X-ray diffraction analysis indicates that 1 is an ionic compound and its components in the crystal are associated by extended charge-assisted hydrogen bonds between cations and anions and other interactions such as CH…N bonds and - stacking into supramolecular chains (Fig. 1a,b). The use of Hirshfeld surface analysis in combination with fingerprint plots demonstrates that these interactions are important for both local packing and crystal packing: the close contacts are associated with relatively weak H...H (45,9%), H...O/O...H (30,8%), C...H/H...C (8,8%), and Cl...H/H...Cl (12,1%) interactions. The total dnorm surface (ranging from 0,4791 (red) to 1,3073 (blue) Å) has been shown in Figure 1c, in which the red points (spherical depression spots) correspond to O–H...O interactions in the crystal. For examination of the influence of - stacking on the molecular packing, an analysis of the Hirshfeld surface mapped over the shape-index properties has been made (Fig. 1d). a b Fig. 1. Molecular structure of 1 showing intermolecular hydrogen bonds (a). Fragment of a hydrogen-bonded supramolecular chain (b). The Hirshfeld surface of 1 plotted over dnorm (c) and shape-index (d).