本篇論文主要分成兩系列。所有化合物經由1H-NMR、13C-NMR與元素分析鑑定其結構及純度；液晶相性質則分別利用光學顯微鏡POM觀察其相的種類、使用熱微差掃描分析儀DSC測量其相變化時的溫度與熱焓值，最後使用變溫X-ray粉末繞射儀，再次確認液晶相種類，並推測其分子排列與推疊情形。 系列一的實驗主要為合成與研究polycatenar液晶材料1a-1d，其結構為：四個芳香環組成的硬端中心，外圍連接兩條、四條或六條軟端烷氧鏈。烷氧鏈的數目與(或)位置影響此類化合物的液晶相變化。除此之外，固定外圍烷氧鏈數目與位置，合成化合物2a-2d，觀察延長中心硬端長度時的相變化，嘗試歸納分子結構與液晶性質之間的關聯性。 系列二合成具有雙雜環Isoxazole及Pyrazole結構之有機液晶分子。探討當烷氧鏈為不同碳數時(n = 8、10、12、14、16)對液晶相的影響。成功養出同樣碳鏈長度n = 6三種化合物4b、5b及6b的單晶(含雙雜環Isoxazole、Pyrazole及合環反應之前驅物)，藉用X-ray單晶繞射分析的數據，探討分子間的作用力與平面性。 In this work, two series of mesogenic compounds were prepared and studied. All compounds were characterized and identified via 1H-NMR, 13C-NMR, mass analysis and elemental analysis. The mesophases were studied and investigated by POM and DSC, and the structures of the mesophases were also confirmed by variable temperature X-ray diffraction experiments. In the first series, mesogenic compounds 1ad were synthesized and their mesomorphic behavior investigated. These fourrings aromatic compounds, considered their molecular shapes as polycatenar mesogens attached with two, four or six terminal flexible aliphatic chains exhibited interesting mesomorphic behavior. Compounds 2ad with an extended aromatic ring as central core were also prepared and studied. The formation of mesophases was found to be sensitive to the number and/or positions of alkoxy chains. The correlation between the molecular structures and the mesomorphic properties will be discussed. In the second series, a new type of mesogenic heterocyclic compounds derived from bisisoxazoles and bispyrazoles 46b were prepared and studied. Both heterocycles were considered as electron-deficient. Their mesomorphic behavior was dependent on the carbon lengths attached. A single crystal Xray determination was resolved and molecular interactions on the effect and/or formation of mesophases in these compounds were studied in details
