A new series of unsymmetrically 1,1'-disubstituted ferrocene derivatives, 1-[4'-(4-substitutedbenzoyloxy)biphenyl-4-oxycarbonyl]-1'-alkoxycarbonylferrocene, was prepared and their phase transition behavior was studied by a differential scanning calorimeter and a polarizing microscope. Some structural parameters, such as the length of the alkyl chain and the nature of the terminal substituent, have been modified. In the case of no substituent at a terminal position of the mesogenic group, the derivative showed no liquid crystallinity. Monotropic liquid crystalline phases were observed for the derivatives having a polar terminal group. The compounds with a flexible alkoxy chain as the terminal group gave rise to an enantiotropic nematic phase.