This review provides an overview of the chemistry, structure and potential applications of 1-(acyl/aroyl)-3-(mono-substituted) and 1-(acyl/aroyl)-3,3-(di-substituted) thioureas, with general formula R 1 C(O)N (1) HC(S)N (3) R 2 R 3 . In recent years, the title compounds have found extensive applications as ligands in coordination chemistry. The effect that nitrogen substituents exert on the intra-and intermolecular hydrogen-bonding interactions is discussed, including their role on the coordination properties displayed by these ligands. Novel applications of transition metal complexes bearing 1-(acyl/aroyl)-3-(mono-and di-substituted) thioureas are introduced. Biological aspects are also highlighted. As recently demonstrated, high-throughput screening assay and structure-activity analyses are feasible for this class of compounds. The chemical versatility of 1-(acyl)-3-(substituted) thiourea molecules and the derived metal complexes, together with the possibility of determining detailed structural properties, join biological applications in a promising interdisciplinary approach. The bibliography includes 382 references with emphasis on the literature appearing after 2007.