A film, and a light-emitting device (e.g., an OLED) incorporating the film as an emission layer, have luminescent emitters that are maintained in a desired orientation by incorporating them into a crystalline framework material, such as a metal-organic framework (MOF), covalent organic framework (COF), or porous coordination polymer. The crystal structure in the film has at least one crystallographic axis that is aligned substantially parallel to the planar surface of the film and/or the planar surface of a device substrate on which the film is deposited or grown. The luminescent emitters are held and oriented in the unit cells of the crystalline framework material such that their transition dipoles are substantially parallel to the crystallographic axis, which is in turn substantially parallel to the surface of the film or emission layer of the device through which light is emitted, resulting in improved outcoupling of light.