<p>A significant topic in transport problems emerges when a flow’s characteristic length scale approaches the granular or molecular dimensions of the medium. The use of micropolar fluid theory, which considers the particle rotation and coupling stresses that Newtonian models ignore is motivated in such situations by the importance of the intrinsic rotation and microstructural motion of the material constituents. Applications in thermal engineering, biological transport, lubrication, energy systems and polymer manufacturing all depend on an understanding of heat transfer in micropolar fluids. Recent developments in the heat transfer behaviour of micro-structured fluids under the impact of internal heat generation or absorption, thermal radiation, chemical reactions, Soret-Dufour effects, viscous dissipation, magnetic field and porous media are systematically examined in this study. Using major scientific databases, a PRISMA-guided literature assessment was carried out with an emphasis on peer-reviewed research that includes at least one multi-physics interaction and was published between 2021 and 2025. Excluded studies lacked micro-structured fluid formulations or thermal analysis. Significant obstacles still exist despite significant advancements, such as simplified material characteristics, little experimental confirmation and limited handling of intricate geometries and three-dimensional effects. By considering all these aspects, this review highlights important research gaps and offers a cohesive framework for comprehending multi-physics heat transfer in micropolar fluids. For researchers and engineers working on microfluidic systems, sophisticated thermal modelling and energy-related applications utilizing micro-structured fluids, the current review meant to act as a guide and roadmap.</p>