1-hexadecyl-4-(1-hexadecylpyridin-1-ium-4-yl)pyridin-1-ium,dibromide

1-hexadecyl-4,4'-dipyridinium bromide

1-butyl-4-(1-butylpyridin-1-ium-4-yl)pyridin-1-ium

1-butyl-4-pyridin-1-ium-4-ylpyridin-1-ium

N-ethyl-4,4'-bipyridine