||Recently, hyperbranched conjugated polymers are advantageous over there linear counterparts in high solubility, good processability, and minimization of unfavorable intermolecular interactions and crystallization. In addition, as hyperbranched conjugated polymers have many peripheral chromophores, they will prefer forming a globular structure with generations. Lectins are carbohydrate-binding proteins that mediate important biological processes such as cell growth, the inflammatory response and viral infections. A number of sensors for lectins have been developed using different principles in the sensor design. Among them, fluorescence-based lectin sensors have been utilized a sugar-containing probe molecule. Herein, we have designed and synthesized water-soluble conjugated polymer containing mannose group for use as a lectin sensor. We studied change of emission intensity of mannose-modified hyperbranched conjugated polymer by lectin.