In aqueous medium at pH 6, cadmium acetate dihydrate combines with 4,6-dimethylpyrimidine-2-thiol to form a centrosymmetric Cl, S-bridged complex having zwitterionic terminals. The zwitterionic nature of this complex is evidenced by its pH and conductance values in methanol solution. It crystallizes in the space group P21/c (Z = 4 asymmetric units, two molecules), each molecule being uncommonly characterized by a centric Cd(II)S2Cl2N2 as well as two acentric and anionic Cd(II)S3ClN2 coordination chromophores with counter cationic ligands. Relevant literature reports indicate a template relation between the structural designs of this complex and hydrated cadmium acetate, the metalorganic precursor. Packing of molecular motifs through weak C–H···N and strong charge-enhanced Nδ+–H···N interactions generate the crystal structure with numerous screw–glide related small voids. Attempt has been made to rationalize the crystallochromic nature of the complex (pale green in solution, pale orange while crystalline) by time dependent DFT and ZINDO/S studies.In aqueous medium, cadmium acetate combines with 4,6-dimethylpyrimidine-2-thiol to form a centrosymmetric, trinuclear complex with zwitterionic terminals. The crystallochromic behaviour of this complex is investigated by quantum chemical treatment.