本論文之液晶分子研究以五炔苯基苯的雙聚物為主體，化合物A至D已由實驗室成員合成，其中具烷氧鏈者易形成盤狀向列相，而具烷鏈者則易形成筒狀相。本文先純化化合物A至D並取得光譜數據，再另外合成具長烷鏈的化合物E，以比較液晶行為。 In this thesis, the liquid crystal properties of dimers of pentakis(phenylethynyl)benzene were studied. Compounds A to D, synthesized by former members, are further purified to obtain complete spectroscopic and liquid crystalline property data. Disc dimers with alkoxy chains tend to form the discotic nematic phase. Disc dimers with alkyl chains are prone to form the columnar phase. A new disc dimer E with longer alkyl chains has been prepared to show lower transition temperatures.