The steric hindrance at the 2-position of the fluoran ring and its influence on the electronic absorption spectrum were studied by semiempirical MO calculations. All fluoran dyes in this study gave two or more conformers by using structure optimization, Spectral changes and band shapes with respect to the steric hindrance of the amino group at the 2-position are discussed on the basis of calculations performed for a variety of conformations. A good correlation between the wavelengths of separated peaks and those of calculated peaks was obtained.