Hexaethynylbenzene is a highly symmetrical, star-shaped organic molecule featuring a central benzene ring core with six ethynyl (-C≡CH) substituents. This unique structure endows it with a rigid, planar geometry and multiple reactive sites, making it a valuable building block in advanced materials chemistry. Its primary application is as a key precursor for the synthesis of functional organic materials. The six terminal alkyne groups can undergo various cross-coupling reactions (e.g., Sonogashira coupling) and cyclotrimerization to construct extended π-conjugated systems. It is extensively used to synthesize graphdiyne-like two-dimensional carbon networks, organic semiconductors, and highly porous covalent organic frameworks (COFs) and metal-organic frameworks (MOFs). These materials are investigated for applications in organic light-emitting diodes (OLEDs), organic photovoltaics (OPVs), gas storage, and catalysis. Due to its high reactivity and tendency to polymerize, hexaethynylbenzene requires careful handling under inert atmosphere and low-temperature storage. It serves as a fundamental synthon for designing novel carbon-rich architectures with tailored electronic and structural properties.