This paper analytically investigates unsteady, laminar, magnetohydrodynamic (MHD) mixed convective oscillatory flow of two immiscible viscous fluids through a horizontal two-phase channel. The channel consists of a porous upper region (Region~I, $0 \le y \le h$) and a non-porous lower region (Region~II, $-h \le y \le 0$), separated by a permeable interface, with a uniform transverse magnetic field $B_0$ applied normal to the flow. The governing equations incorporate thermal buoyancy ($Gr$), concentration buoyancy ($Gc$), Darcy porous resistance, thermal radiation (Rosseland approximation), volumetric heat generation/absorption, first-order destructive chemical reaction, and the Soret effect... More >