The present disclosure provides novel dihydrophenanthrene (DHP)-cyanine and DHP-squaraine fluorescent compounds and water-soluble polymers thereof. The DHP-cyanine and DHP-squaraine fluorescent compounds and polymers can be excited using UV, violet, blue, yellow, green, red, or NIR wavelengths. The fluorescent dyes may be conjugated to antibodies for detection of target analytes in biological samples and are suitable for use in flow cytometry analyses.

The present invention relates to near-infrared fluorescent heptamethine dyes and conjugates of heptamethine dyes with favourable biodistribution and bleaching properties.