The notions of complex systems and emergence are rather closely related. Nevertheless, both are prevalently identified after a dynamics of the system is known and sufficiently understood. This article focuses on the possibility for drawing conclusions on one of these notions if some data about the other are known. On the one hand, we analyse the possibility of determining the likelihood of emergent phenomena occurrence during the evolution of a complex system dynamics. On the other hand, we analyse the possibility of predicting dynamics of a complex system if one knows some characteristics of emergent phenomena in it. The basis of the approach consists in attributing analogues of quantities from physics to a model of a complex system. The emphasis is on relating a complex system’s evolution and localised-in-time emergent phenomena.