The present invention relates to a compound based on cyanine scaffold for diagnosing sepsis by selectively detecting glutathione. The compound based on cyanine scaffold according to the present invention has the advantages of maintaining its structure in intracellular environment and of reacting selectively to glutathione only among many amino acids containing thiol group (R—SH) such as cysteine, homocysteine, and glutathione, to produce changes in absorption or fluorescence spectrum, making the compound useful for the detection of in vivo glutathione in biosamples and also for the diagnosis of sepsis characteristically displaying the changes of glutathione concentration.