We are currently studying nano size materials comprised of IV^th-group elements of C, Si, Ge and Sn, for achieving new insights to fundamental understanding in solid state physics of nano materials, as well as development of advanced electronic devices in the next generation. The most typical cluster is C₆₀, where sixty carbon atoms are selfassembled to a polyhedral cluster with high symmetry. Other IV^th-group elements like Si, Ge and Sn have recently been noticed to make similar polyhedra of IV₂₀, IV₂₄ and IV₂₈ cage clusters. One of the prominent things on these large size clusters is the fact that various types of crystals can be constructed ranging from van der Waals crystals to covalent ones. Phonons ranging from intra-cluster to lattice vibrations play an important role for determining the electronic states, and such situation is very different from that of the conventional materials. Phonons, conduction-electrons and magnetic-electrons interplay to produce electronic properties that cannot be obtained in the conventional materials. The most important researches in this century shall be nano materials science and technology. We are exploring novel materials on a basis of nano network materials and carrying out experiments towards this future dream.