<p>Yb and Re (Re = Er, Ho) codoped Sr₂ScSbO₆ double perovskite phosphors were synthesized via high-temperature solid-state reaction. Under excitation by a 980&#xa0;nm laser, the Yb³⁺/Er³⁺ codoped sample exhibits weak green emissions at 522 and 558&#xa0;nm, along with a dominant red emission at 660&#xa0;nm, which is attributed to efficient cross-relaxation processes that enhance population of the ⁴F_9/2 level. Notably, the emission intensities are temperature-dependent, resulting in distinct and visible changes in emission color with increasing temperature. Temperature sensing based on the fluorescence intensity ratio (FIR) demonstrates a maximum relative sensitivity of 0.73% K⁻¹ at 490&#xa0;K and an absolute sensitivity of 1.43% K⁻¹ at 730&#xa0;K. In contrast, the Yb³⁺/Ho³⁺ codoped sample exhibits dual green (543&#xa0;nm) and red (661&#xa0;nm) emissions, along with superior performance in high temperatures, achieving a relative sensitivity of 0.59%·K⁻¹ and an absolute sensitivity of 0.42%·K⁻¹ at 670&#xa0;K. These results suggest that the Yb³⁺/Er³⁺ system is more suitable for low-to-intermediate temperature sensing, while the Yb³⁺/Ho³⁺ system is better suited for high-temperature optical thermometry applications.</p>