A co-crystal of 2-(1′-pyrenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl with octafluoronaphthalene

2-(1′-Pyrenyl)nitronylnitroxide (PyrNN) forms a 2 : 1 : 2 co-crystal with octafluoronaphthalene (OFN) and entrained solvent dichloromethane (DCM), in which the radical is “shepherded” into forming chains of radical–radical contacts on the peripheries of (PyrNN–OFN–PyrNN)n π-stacks, giving weak, low dimensional inter-radical antiferromagnetic exchange interactions.