Chlorophyll b wani launin kore ne da ake samu a cikin chloroplasts na shuke-shuke, algae, da wasu wasu kwayoyin halitta na photosythetic. Yana daya daga cikin manyan nau'ikan chlorophyll, tare da chlorophyll a, kuma yana taka muhimmiyar rawa a cikin photosynthesis, tsarin da tsire-tsire ke canza makamashin haske zuwa makamashin sinadarai. Chlorophyll b yana ɗaukar haske da inganci a tsawon tsayi tsakanin 450 zuwa 500 nanometers kuma tsakanin 630 zuwa 660 nanometers.