The present invention provides polymeric materials arranged as photonic crystals, or portions of photonic crystals, having properties which can be easily tuned over a large range of wavelengths upon exposure to an external stimulus. In some embodiments, the photonic crystals comprise at least one portion which can undergo a change in a physical, chemical, dielectric, or other property upon exposure to an altering stimulus, resulting in a change in a diffracted wavelength of electromagnetic radiation (e.g, light) by the photonic crystal. Embodiments of the invention may advantageously exhibit large stop band tunability and rapid response times. Photonic crystals of the invention may be useful in a wide variety of applications, such as colorimetric sensors, active components of simple display devices, electrically controlled tunable optically pumped laser, photonic switches, multiband filters, and the like.