2,2'-Dipyrromethene
2 , 2'-Dipyrromethene , often called just dipyrromethene or dipyrrin , is a chemical compound with formula whose skeleton can be described as two pyrrole rings connected by a methyne bridge =CH– through their nitrogen-adjacent ( position-2 ) carbons; the remaining bonds being satisfied by hydrogen atoms . 
<triplet> 2,2'-Dipyrromethene <subj> chemical compound <obj> instance of <triplet> pyrrole <subj> chemical compound <obj> instance of <subj> nitrogen <obj> has part <subj> hydrogen <obj> has part