In this chapter, the most important applications of fullerene derivatives in materials science are presented especially to understand the significant contributions of fullerene chemistry to the development of new materials. A general overview of the state-of-the-art in this interesting field is given, including a number of representative and most recent examples of donorâ acceptor systems, organic electron devices, superconductors, fullerene aggregates, nonlinear optics applications, liquid crystals and fullereneâ inorganic hybrids.