Research presented in this book focuses on the novel dispersion pro-perties and some of the first-ever applications of dispersion-engi-neered photonic crystals. By engineering the dispersion of a 2D photonic crystal, a flat cylindrical lens was designed and fabricated, through which 2D negative refraction and 2D subwavelength imaging were experimentally demonstrated in both amplitude and phase. Further effort was then focused on materials exhibiting full 3D negative refraction due to their practical applications and theoretical interests in them. Negative refraction flat lenses provided super-re-solution and curvature-free imaging, which can find potential appli-cations in improving the performance of optical tweezers. In addition to negative refraction, self-collimation of electromagnetic waves in 2D and 3D photonic crystals was also theoretically investigated and experimentally demonstrated. The uniqueness of this work is that dispersion properties of both 2D and 3D photonic crystals are explored, and experimental device characterization is demonstrated in both amplitude and phase.