Crystallization and phase separation are two intriguing phase transitions in nature and have been intensively studied in the past decades. Recently, the mechanism of simultaneous or interactive transitions of crystallization and phase separation of binary blend has became a popular research topic due to its importance to both fundamental understandings as well as technological applications. In this study, the interactive phase transitions are further extended to a dynamically asymmetrical system. Two kinds of phase diagrams were obtained in this dynamically asymmetric blend poly(methyl methacrylate) (PMMA) and poly(ethylene oxide) (PEO). The experimental work was also expanded to the highly immiscible blend of isotactic polypropylene (iPP) and PMMA. There was phase inversion for the minor PMMA-rich phase and the transient network structure underwent hierarchical growth on different length scales. The interface may play the role as substrate to assist heterogeneous crystallization. The selection of different initial states, together with the thermal and temporal paths of processing offers a large number of possibilities for morphology and properties control for the same pair of polymer blends than we can normally do with a symmetrical blend. Keywords: Polymer Blends, Crystallization, Glass Transition, Dynamic Asymmetry