This paper describes a facile and green strategy for the synthesis of yttrium oxide nanoparticles (Y2O3 NPs) by a straightforward process using Liriope platyphylla rhizome extract as the reducing agent and yttrium nitrate hexahydrate as the sole precursor without other additives. The crystallinity, surface chemistry, morphology, elemental composition, and thermal properties of the synthesized NPs are thoroughly investigated. The synthesized NPs shows remarkable catalytic activity for the construction of biologically interesting 1,3-thiazolidin-4-ones.