Switchable molecular materials are a diverse class of molecular organizations which includes single-molecule magnets (SMMs), spin crossover (SCO) complexes, single-chain magnets (SCMs), metal-to-metal electron transfer (MMET) systems, etc. SMMs are a class of paramagnetic molecular entities displaying slow dynamics in their magnetization. The intriguing complexes show substantial advantages in magneto-structural analysis due to their negligible magnetic exchange interactions and convenient structural regulation. With a major focus on Lnbased SMM, numerous mononuclear complexes incorporating -diketone ligands including dibenzoylmethane (dbm), acetylacetonate (acac), ferrocenoylacetonate, fluoro substituted βdiketone with different bidentate nitrogen donor coligand e.g. 2,2'-bipyridine (bpy), 1,10phenanthroline (phen), 2,2'-bipyrimidine (bpm) and their azacyclo-derivative have been studied to investigate Dy-based SMMs. These studies report that magnetic anisotropy of Dy(III) based complexes is affected by the ligand field strength, local symmetry around the mental centre, etc.