Thiosemicarbazones, an important class of sulphur donor ligands, and their transition metal complexes are known for their versatile applications in the fields of (bio)catalysis, pharmaceuticals and sensors. There were numerous investigations on the biological and medicinal applications of these compounds, which were thoroughly discussed and reviewed. In the past few decades, a lot of research works have been done on the catalytic activity of thiosemicarbazone-based complexes towards various organic transformations. In this article, an attempt has been made to review the homogeneous catalytic applications (transfer hydrogenation of carbonyl compounds, N-arylation of heterocyclic amines, oxidation of alcohols, cyclopropanation of olefins, olefin epoxidation, N-alkylation of amines, amidation of alcohols, hydration of nitriles and C–C cross-coupling reactions) of transition metal complexes containing thiosemicarbazone ligands.