2,6-二氯酚靛酚（英语：2,6-dichlorophenol Indophenol，简称DCPIP或DPIP）为用于氧化还原指示剂的化合物。当DCPIP处于氧化态时呈现蓝色，最大吸光值为600奈米；还原态时则为无色。

DCPIP可用于侦测光合作用的反应速率，为希尔反应家族之一。当该指示剂暴露于光合作用系统时，会因化学还原反应而脱色。DCPIP比起铁氧还蛋白拥有较高电子亲合能，可被光合作用的电子传递链还原，作为光合作用中最终电子载体NADP的替代品。当DCPIP因还原反应而逐渐脱色时，可经由分光光度法测量到其透光率上升。

2,6-Dichlorophenolindophenol (DCPIP or DPIP) is a chemical compound used as a redox dye. When oxidized, DCPIP is blue with a maximal absorption at 600 nm; when reduced, DCPIP is colorless.

DCPIP can be used to measure the rate of photosynthesis. It is part of the Hill reagents family. When exposed to light in a photosynthetic system, the dye is decolorised by chemical reduction. DCPIP has a higher affinity for electrons than ferredoxin and the photosynthetic electron transport chain can reduce DCPIP as a substitute for NADP, that is normally the final electron carrier in photosynthesis. As DCPIP is reduced and becomes colorless, the resultant increase in light transmittance can be measured using a spectrophotometer.