1-Pyrenecarboxylic acid is an organic compound featuring a pyrene core functionalized with a carboxylic acid group. This structure combines the extended π-conjugation and strong fluorescence of pyrene with the reactivity and coordination ability of a carboxylic acid. It is a yellow to orange crystalline powder. Its primary applications are in the field of materials science, particularly as a key building block for organic semiconductors and functional materials. The carboxylic acid group allows for covalent attachment to surfaces, metal ions, or other molecular units, enabling the construction of supramolecular assemblies, coordination polymers, and self-assembled monolayers. It is widely used in the development of organic light-emitting diodes (OLEDs), organic photovoltaics (OPVs), and as a fluorescent probe or sensor due to its sensitive emission properties to the local environment. Additionally, it serves as a versatile organic synthesis intermediate. The acid group can be readily converted into esters, amides, or acid chlorides, facilitating its incorporation into more complex molecular architectures for research in photophysics and electrochemistry.