The hydrothermal synthesis and optical properties of Nb 5? -doped lithium metasilicate and lithium disilicate nanomaterials were investigated. The microstructures and morphologies of the synthesized Li 2-2x-Nb 2x SiO 31d and Li 2-2x Nb 2x Si 2 O 51d nanomaterials were studied with powder X-ray diffraction and scanning electron microscopy techniques, respectively. The synthesized niobium-doped lithium metasilicate and lithium disilicate nanomaterials, respectively, are isostructural with the standard bulk Li 2 SiO 3 (space group Cmc2 1 ) and Li 2 Si 2 O 5 (space group Ccc2) materials. Photoluminescence spectra of the synthesized materials are studied. The measured optical properties show dependence on the dopant amounts in the structure.