In this study, the non-Darcy Three-Component Marangoni (NDTCM) convection issue is investigated in closed form using a non-Darcy model for the porous layer with constant heat source/ sink (HSS) and uniform vertical magnetic field in a two-layer system with a porous layer under a fluid layer. This two-layer construction has a rigid and adiabatic lower enclosure for the porous layer and a free adiabatic/ isothermal upper enclosure for the liquid layer. The thermal Marangoni numbers (TMNs) for lower rigid and upper free boundaries with surface tension, depending on both temperature and concentrations, are determined in closed form for two cases of temperature boundary conditions (TBCs), Case (i) Adiabatic–Adiabatic and Case (ii) Adiabatic–Isothermal. The ordinary differential equations are solved by an exact method of solution to attain an analytical expression for the Marangoni number. The impacts of applicable factors are discussed elaborately versus thermal ratio and shown graphically using MATHEMATICA. It is noticed that case (i) TBC is stable as the eigenvalue obtained is higher than that for case (ii) TBC for the fluid layer dominant (FLD) two-layer systems.