4-Ethynylbenzoic acid may be used in the synthesis of N-(4-ethynylphenylcarbonyl) L-glutamic acid diethyl ester, a precursor for synthesizing glutamic acid-based dendritic helical poly(phenylacetylene)s. It can also be used to prepare zinc porphyrins attached to various cyclic aromatic hydrocarbon substituents, which can act as potential photo-sensitizers for dye-sensitized solar cells (DSSCs). This product was previously listed as CBR01612. 4-Ethynylbenzoic acid may be used in the synthesis of N-(4-ethynylphenylcarbonyl) L-glutamic acid diethyl ester, a precursor for synthesizing glutamic acid-based dendritic helical poly(phenylacetylene)s. It can also be used to prepare zinc porphyrins attached to various cyclic aromatic hydrocarbon substituents, which can act as potential photo-sensitizers for dye-sensitized solar cells (DSSCs). This product was previously listed as CBR01612.