Abstract
Chloroplasts photochemically reduce 1,1'-trimethylene-2,2'-dipyridylium dibromide and concurrently form adenosine triphosphate. Reduced trimethylene dipyridyl in darkness will reduce spinach ferredoxin, Clostridium pasteurianum ferredoxin, nicotinamide-adenine dinucleotide phosphate, and other viologen-type dyes.