Pentamethylcyclopentadienylrhodium(III) chloride dimer is a specialty organometallic catalyst widely used in advanced organic synthesis. It serves as a key precursor for Cp*Rh(III) complexes in C-H activation reactions, enabling selective functionalization of C-H bonds in arenes, heteroarenes, and other substrates. This compound is particularly valuable in the synthesis of pharmaceuticals, agrochemicals, and fine chemicals through directed C-H borylation, alkylation, arylation, and annulation processes. Its high stability and tunable reactivity make it suitable for asymmetric C-H functionalizations, facilitating the stereoselective construction of complex molecules. Additionally, it is employed in materials science for the development of functionalized polymers and in mechanistic studies of organometallic catalysis. As a niche rhodium-based catalyst, it plays a crucial role in efficient, atom-economical synthetic methodologies in both academic research and industrial applications.