O‐Phthalaldehyde: A Versatile Chemical with its Roles and Future Perspectives

Ortho‐Phthaldehyde (OPA) is one of the isomers of benzenedicarbaldehydes. It exhibits distinctive chemical properties stemming from the closely attached dicarbaldehyde groups. Since its development, it has been widely employed as a potent disinfectant, owing to its inherent antimicrobial properties. OPA has the ability to form a fluorescent product with primary amines, making it useful for detecting and estimating various biogenic amines, peptides, and proteins in bodily fluids. Moreover, the combination of thiol and amine with OPA produces a more sensitive fluorogenic compound, significantly enhancing the sensitivity and specificity of OPA‐based analytical techniques. This review summarizes recent developments in biochemical analysis using OPA. It also discusses key achievements in the development of photoactive polymers. Additionally, it covers the use of OPA as a synthetic precursor to achieve small molecules with unique structures that have become increasingly important in various fields of scientific research from 2004.