Host-dependent optical dephasing of the zero-phonon line of two organic dye molecules doped in several cross-linked polyvinyl alcohol (PVA) derivatives was studied by using an incoherent photon echo technique. It was found that the optical dephasing time of the zero-phonon line increases with increasing the length of the cross-link introduced to the PVA backbone. Our results indicate that, by the introduction of the cross-link, the effect of the two-level tunneling system in PVA on optical dephasing of a doped dye is greatly reduced and the dephasing time of the dye becomes longer than that in the PVA without the cross-link. The decrease of the optical dephasing can be interpreted by assuming a void space in PVA, which is created near to an introduced cross-linker.