Poly(o-hydroxyamide)s as polybenzoxazoles precursors were synthesized by polycondensation from 2,2'-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and various bis-acids. And the polymers were modified to acid-sensitive polyamides by introducing tetrahydropyran in order to impart photosensitivity. A study of optical transmittance at 365 nm, according to the chemical structure of bis-acid, revealed that the polymer derived from 4,4'-oxydibenzoic acid showed better optical transparency than those from other bis-acids. This tendency of optical transmittance could be explained by formation of charge transfer complex. In case of the polymer derived from 4,4'-oxydibenzoic acid, the electron accepting characteristic of bis-acid is reduced by introduction of electron donating group, -O-. Thus, optical transmittance increased due to the diminished formation of intramolecular charge transfer complex. In addition, the optical transmittance increased with increasing the THP content in the polymer. This is attributed to the reduced intermolecular interaction by the loosening of the packing density of the polymer chain.