Understanding the microstructural evolution of hydrating cement paste is fundamental to predicting the mechanical performance and durability of cement-based structures. While thermodynamic equilibrium calculations, often coupled with kinetic models for clinker dissolution rate, have become a convenient and reliable approach for estimating phase assemblage during hydration, their broader potential lies in integration with complementary microstructural and multi-scale modelling frameworks. Thermodynamic simulations provide quantitative predictions of phase assemblage, pore solution chemistry, and reaction degrees as functions of time, temperature, and composition. These solid- and liquid-phase assemblage evolution outputs can be coupled with digital image-based hydration models, phase-field approaches, and multi-scale materials modelling techniques by linking chemistry-driven phase evolution with physically resolved microstructural representations. Coupled frameworks enable the prediction of elastic properties, creep behaviour, compressive strength, transport parameters, and formation factor. Existing examples of thermodynamic and microstructural coupling, along with future directions, are discussed in the present work. In this conceptual perspective, thermodynamic modelling is positioned as the backbone of an integrated predictive framework for evolving cementitious matrices. When systematically coupled with microstructure-resolving approaches, thermodynamic simulations provide a pathway to move beyond empirical correlations toward binder chemistry-informed prediction of mechanical and durability-related properties. This integrated strategy has significant potential to accelerate materials design and optimize low-clinker and blended cement systems in a performance-based context.