Medium-manganese steels are seen as a strong contender for the 3rd generation of Advanced High Strength Steels (AHSS) for automotive applications, primarily due to its excellent strength-ductility combination and affordable cost of production. Recent research indicates that the intriguing mechanical properties of these steels are linked to the stacking fault energy and the stability of the retained austenite. In order to further enhance their mechanical properties, the alloy chemistry and microstructure need to be suitably designed. The present work aims at developing two grades of medium-manganese steel and establishing their thermomechanical processing routes with the aid of physical metallurgy principles and computational alloy thermodynamics based on the CALPHAD approach. Due consideration will be given to factors such as weldability, coatability, and formability while choosing the alloy chemistry. Results indicate that the grades developed in the present investigation show excellent mechanical properties with a high value for the product of tensile strength and uniform elongation (>35,000 MPa%). Tensile behaviour of the steel showed a complex stress-strain curve exhibiting a staircase kind of strain hardening. Subsequent studies will focus on exploring the various aspects of the strain hardening behaviour observed and the role of TRIP and TWIP effects on the same. A detailed study will be carried out to understand the response of individual phases by analyzing the strain partitioning among them and their impact on the serrated plastic flow of the steel. We also propose to evaluate the plastic deformation behavior of these steels on a wide range of strain rates (10-3 to 103 s-1) and their effect on the microstructural evolution and the strain hardening behavior.