We report crystal structure of TIPS-pentacene thin films studied by two dimensional grazing incidence x-ray diffraction (2D-GIXD). Thin films were fabricated by dry and wet processes, and precisely compared the crystal structures of the fabricated films. Slight differences in the unit cell parameters are found in the films. Furthermore, a new polymorph is identified in the film fabricated at sufficiently low substrate temperature, - 166 degrees C. The unit cell parameters of the new polymorph are determined by analyzing the 2D-GIXD pattern.