Data-processing and optical communication systems that allow controlling intensity and polarization state of light via external magnetic fields require compact, efficient, and low-cost magnetic materials. It is these properties of magnetic materials that are the subject of the present chapter. Owing to their strong linear and nonlinear magneto-optical responses along with unique optical characteristics, magnetophotonic crystals have already found applications in electronics. As a particular example, film-type optical isolator/circulator devices have been proposed. Recent renewed interest in magneto-optical spatial light modulators has resulted from the development of optical volumetric recording using holography, particularly, collinear holography. Here we focus on reviewing experimental and theoretical studies of light coupling to various artificial magnetic nanostructured media and nanocomposites providing strong magneto-optical responses and having miniature dimensions. We first examine properties of different types of MPCs. Then, the magnetorefractive effect of various materials is considered, an enhancement of the magnetorefractive response is demonstrated for structures fabricated in the use of the magnetophotonic crystals' concept. Finally, the influence of localized surface plasmon resonances on optical and magneto-optical properties of bismuth-substituted yttrium iron garnet films impregnated with nanoparticles of noble metals is discussed. Another promising way to enhance Faraday rotation is to exploit the regime of extraordinary transmission for systems comprising a perforated noble-metal film supporting transmission resonances and a magnetic material.