<p>In this article, we present the synthesis of a series of composite materials (glass with nanophosphor) incorporating samarium-doped borotellurite glass (Sm:BT) and Eu:Y₂O₃ nanophosphor using a cosintering technique. Structural analysis reveals the coexistence of glassy and nanocrystalline phases within the material. Comprehensive spectroscopic investigations were conducted through methods such as UV–visible-infrared absorption, and laser spectroscopy in addition to estimation of optical parameters, including Urbach energy, refractive index, and bandgap. The photoluminescence spectra show a combination of sharp, red-dominant emissions from Eu³⁺ ions and broad emission bands from Sm³⁺ ions, spanning from 509 to 1410&#xa0;nm. Laser spectroscopy confirms effective interactions between Eu³⁺ and Sm³⁺ ions, even though these active species are encapsulated in different matrices via radiative energy transfer. Notably, the sharp emission from Eu³⁺ in the nanophosphor broadens when integrated into the glass matrix. The addition of nanophosphor to the glass not only extends the emission spectrum into the infrared range but also improves control over color modulation and allows for higher concentrations within the lattice. Color analysis was performed by estimating the CIE coordinate&#xa0;and CCT values, indicating precise tuning of the overall emission color hue.</p>