2,2'-Dipyrromethene, often called just dipyrromethene or dipyrrin, is a chemical compound with formula C9H8N2 whose skeleton can be described as two pyrrole rings C5N connected by a methyne bridge =CH– through their nitrogen-adjacent (position-2) carbons; the remaining bonds being satisfied by hydrogen atoms.

[1] 2,2'-Dipyrromethene and its more stable and easily prepared derivatives—formally obtained by replacing one or more hydrogen atoms by other functional groups—are important precursors for the family of BODIPY fluorescent dies.

As another possibility, one may condense a substituted pyrroles with a 2-acylpyrrole; this route allows the synthesis of unsymmetrical dipyrromethenes.

[4] The so-called BODIPY dyes can be obtained by reacting 2,2'-dipyrromethene or its derivatives with boron trifluoride-diethyl ether complex (BF3·(C2H5)2O) in the presence of triethylamine or 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU).

For example, the derivative anion 5-phenyl dipirrinato (pdp) forms the neutral iron(III) complex Fe(pdp)3 (dark green monoclinic crystals, soluble in benzene, orange solution in dichloromethane), where the Fe3+ ion is coordinated to six nitrogen atoms of the dipyrrin cores in distorted octahedral geometry.