The Methyl Thymol Blue Complexon is widely used as a metallochromic indicator in complexometric titrations, particularly for the determination of metal ions such as calcium, magnesium, and rare earth elements. It is especially effective in EDTA titrations, where it provides a clear color change at the endpoint, typically from blue to red or violet, depending on the metal ion being analyzed. This property makes it valuable in water hardness testing and in analytical chemistry for quantifying metal concentrations in various samples. Additionally, it is employed in biochemical research for studying metal ion interactions and in industrial processes where precise metal ion detection is critical.