Dielectric photonic band gap materials have received broad attention due to their distinguished performance in optical devices, microwave generation and laser acceleration. We have theoretically studied photonic band structure parameters of ZnX (X = S, Se, Te). The photonic band structure calculations are performed using the MIT photonic-bands package (MPB) to calculate eigenmodes frequency domain of Maxwell's equations with periodic boundary conditions. Eigenmodes are calculated in Fourier domain. Model calculations are based on two-dimensional periodic crystal structure. The lattices consist of cylindrical rods and gaps between the rods filled with air. Single-site zinc blende lattices are considered. In order to get "gap maps" we have calculated the gaps as a function of radius of the rods. Moreover we have calculated the nature of guided modes in line defect waveguide. Our results are in good agreement with those in the literature.