 Phosphorus derivatives (based on 4,5,6-triphospha[3]radialene) have also been reported.Phospharadialenes have been investigated as quantum efficiency improvers in solar cells Hexakis[4-(diarylamino)phenyl][3]radialene derivatives have been investigated for their low oxidation potentials.The unsubstituted [4]radialene has been prepared in an elimination reaction of "cis,trans,cis-tetra(bromomethyl)cyclobutane" with sodium methoxide in ethanol.