1-(2-fluorophenyl)-3-pyridin-4-ylurea

1-(4-fluorophenyl)-3-pyridin-4-ylurea

1-(2-methoxyphenyl)-3-pyridin-4-ylurea

triphenyl(pyridin-4-ylimino)-λ⁵-phosphane

4-(pyridin-4-yldiazenyl)naphthalen-1-amine