Table 1. Structural features of the n,n′-bpe series of constitutional isomers.

The twist angle is defined as the angle between the plane defined by the four alkene atoms and the plane defined by either pyridine ring.

Compound	2,2′-bpe	3,3′-bpe	4,4′-bpe
Twist angle φ (°)	7.43	5.17	9.14
Solid-state packing assembly	corrugated chains	approximately planar sheets	planar sheets
Assembly forces	edge-to-face C—H⋯π	edge-to-face C—H⋯π, C—H⋯N	C—H⋯N, face-to-face π–π
Nearest-neighbor alkene separation (Å)	6.09	5.50	5.72