A new series of liquid crystalline compounds, which contained two biphenyl and one p-nitrophenyl groups linked by two flexible spacers, were prepared. The flexible spacer between two biphenyl groups is fixed and consists of nine (odd number) atoms. The compounds showed nematic phase, although some of them exhibited nematic and smectic phases upon cooling. The isotropic-nematic transitional properties depended on the length and parity of the flexible spacers between the biphenyl and p-nitrophenyl groups. Such odd-even effect was in consistency with the feature of liquid crystal trimers. The liquid crystalline properties were compared with those of the related compounds.