The generalized bracket approach to non-equilibrium thermodynamics (NET) is a mesoscopic, microstructure-based framework that allows one to formulate the transport equations in a thermodynamically consistent manner and relate the flow kinematics and mechanical properties to the different length and time scales of the structural components.In this talk, I will present an extension of this framework to mixtures that include components with different physicochemical properties and mixing behaviors. While immiscible and miscible fluids have been described using different approaches in the past, this framework can successfully cover the entire range of miscibility, as confirmed by comparing our OpenFOAM predictions with Y-shaped microchannel measurements. One of the challenges of dealing with multicomponent materials is accounting for their interactions, and frequent backtesting against experimental data is essential. In the future, we will use our OpenFOAM implementation for large-scale simulations of real-world engineering applications such as liquid-liquid extraction.