Used as a coupling agent in organic synthesis and materials science, particularly in the preparation of hybrid organic-inorganic materials. It facilitates the attachment of phenylethynyl groups to silica surfaces or silicate precursors, enhancing compatibility between organic polymers and inorganic matrices. Commonly applied in sol-gel processes to modify surface properties, improve adhesion, and stabilize nanostructures. Also serves as a building block in the synthesis of specialty siloxane-based networks with tailored thermal and mechanical properties.