Used as a selective agent in microbiological media to isolate and identify specific bacteria, particularly Corynebacterium diphtheriae, due to its inhibitory effect on many Gram-positive and Gram-negative bacteria. It is also employed in research settings to study bacterial resistance mechanisms and oxidative stress responses, as tellurite induces reactive oxygen species in cells. In some cases, it serves as a precursor in the synthesis of tellurium-containing compounds for semiconductor or optical materials research.