Abstract: | The synthesis and transition temperatures of a series of 5-(4-alkyl- and 4-alkoxy-phenyl)2-cyanobenzob]furans and a 5-(4'-alkylbiphenyl-4-yl)-2-cyanobenzob]furan are presented. The 2-cyanobenzob]furans show similar mesophase types to the analogous biphenyl and terphenyl compounds, which are obtained by replacing the benzob]furan unit with a phenyl ring. The transition temperatures for the 2-cyanobenzob]furan compounds are always higher than for their biphenyl and terphenyl counterparts, but they are much lower than for the corresponding phenylnaphthalenes. Five mesogenic benzob]furans without a cyano group were prepared as intermediates and these compounds have lower clearing points than their biphenyl analogues. |