A series of 9-substituted 9-(2-cyanomethylphenyl) fluorene derivatives such as 9-hydro-(4), 9-bromo-(5), 9-methoxy-(6) and 9-hydroxy-9-(2-cyanomethylphenyl) fluorene (7) were prepared, and their conformational equilibria (ap⇔sp) were investigated on the bases of their H NMR spectra. It was confirmed that 4 existed as equilibrium mixture (ap/sp=1.5/1) at room temperature, and 7 existed predominantly as the ap-conformer (ap/sp=4.4/1) at -50℃, furthermore, both 5 and 6 existed overwhelmingly as the ap-forms at room temperature and at low temperature, respectively.