Self-assembly of a chlorophyll-based cyclic trimer: Structure and intramolecular energy transfer

► A zinc pyrochlorophyllide a with a 3-pyridyl ligand self-assembles into a cyclic trimer. ► Energy transfer between the Chls occurs with an (11 ± 1 ps)−1 rate constant. ► Surprisingly, Förster theory predicts the rate despite the short Chl-Chl distance.