State-building and the redefinition of the relationship between religion and power are the most central analytical core in the intellectual and practical organization of political Islam movements, the objective crystallization of which can be reread in the two macro-patterns and historical experiences of the Islamic Revolution of Iran and the Muslim Brotherhood of Egypt. Despite the conceptual connection of these two movements under the discourse of political Islam and their commonality in the negation of the secular order and the effort to Islamize the political structure, the paths and processes of state-building in them reflect distinct patterns. The present study, adopting the method of qualitative content analysis and relying on library tools, has analyzed and compared the performance of these two movements in the state-building process. The findings show that the transformation in the ideas of political Islam has led to a profound rearrangement in the patterns of legitimization and mechanisms of power distribution. The Muslim Brotherhood, by fluctuating between the logic of social invitation and intra-system participation, was unable to establish an efficient link between mass mobilization, sustainable institution-building, and the requirements of modern governance; Therefore, its transition from society-building to state-building was met with institutional blockage and fragility of political authority. In contrast, the Islamic Revolution of Iran, relying on the theory of Velayat-e-Faqih and utilizing post-revolutionary institution-building, succeeded in creating a structural break with the previous order and establishing an alternative political order. Comparing these two experiences shows that state-building becomes sustainable when religious legitimacy is combined with institutional capacity, executive efficiency, and the reproduction of political authority in a practical way.