"Complex Networks" is a rapidly developing branch of science whose purpose is to model an interacting group of individuals. Internet, social and economic networks, power plant grids, transportation networks, and brain neuronal network are a few examples of the real world complex networks. The researches in the complex systems group are concentrated mostly on the study of structural properties of networks and dynamics on networks. The structural features of interests are the communities, motifs, clustering coefficients, and spectral properties. The aim of our researches on the dynamics of non-linear models on complex networks is to find the emergent novel collective behaviors arising from the interplay between the dynamical nonlinearity and topology of the networks. Synchronization and epidemic spreading are the two topics in this context, being studied in this group.