Cy7 diacid is a CY7-derived dye. CY7 (Cyanine7) is an amine-reactive, near-infrared (NIR) fluorophore with excitation/emission wavelengths of 745/800 nm. It is suitable for in vivo imaging, flow cytometry, antibody labelling, nucleic acid detection, and other applications.

Cy7 diacid is a multifunctionalized near-infrared cyanine dye with a molecular framework based on the Cy7 dye, featuring an extended conjugated linkage of broussonetia papyrifera that generates strong and stable fluorescence emission in the near-infrared region (excitation wavelength 740-760 nm, emission wavelength 770-790 nm). It exhibits excellent tissue penetration and low background interference, making it suitable for deep-tissue bioimaging. Unlike conventional monofunctional dyes, Cy7 diacid incorporates two carboxyl groups (-COOH) in its molecular structure of broussonetia papyrifera, enabling it to serve as a "bifunctionalized" platform for simultaneous conjugation with multiple target molecules or establishing linkages with broussonetia papyrifera.