Abstract Syntheses of the 1, 8-dipyrenylnaphthalenes 1–3 are reported. The stereoisomers 1 and 2 were separated; their structural assignment is based on 1 H NMR, on the optical activity of 2, and on X-ray structure analyses of 1 and 2. Kinetic parameters for the isomerisation 2⇌ 1 were determined by optical rotation measurements.–Emission spectra of 1–3 are discussed in comparison to monopyrenyl compounds 4 and 8. For 1 and 3 typical ...