Reaction of the in situ deprotonated N-thiophosphorylated thiourea with in aqueous ethanol leads to complexes of the formula . Both compounds crystallise in the triclinic space group P[1 with combining macron] with Z = 2 and the metal cations are found in a tetrahedral S_2S′_2 coordination environment formed by the C–S and P–S sulfur atoms. The crystal structures reveal intramolecular N–H⋯O[double bond, length as m-dash]C hydrogen bonds formed within the fragments. Both structures are further stabilised by intermolecular π⋯π stacking interactions, which are more efficient in . Here, a pronounced dimeric intermolecular aggregate is observed which goes along with a pronounced distortion of the chelate [(S)CNP(S)]− backbone of the ligand upon coordination to as well as a significantly distorted coordination tetrahedron . The aggregation is also reflected in the positive electrospray ionisation (ESI) mass spectrum of the CdII complex, which exhibits peaks for the dimeric cations , and , while for the ZnII analogue only monomeric species were observed. Quantum chemical ETS-NOCV (ADF) calculations confirm the higher stability of dimers in compared with . The π⋯π stacking interactions are prodominantly due to dispersion contributions, though the electrostatic and orbital interaction components are also important. QTAIM (ADF) type calculations additionally quantify the covalent and non-covalent interactions in the momomers.