In the manufacturing process, during our attempts to get a suitable polymorph by reacting the aqueous solution of l-arginine with 3-[4-[2-(phenoxazin-10-yl) ethoxy]phenyl]-2-ethoxypropanoic acid (ragaglitazar) in different solvents, we have encountered various polymorphic modifications. These forms were characterized using differential scanning calorimetry (DSC), thermogravimetric analysis TGA, and powder X-ray diffraction (PXRD) techniques. The polymorphic forms of arginine salt of ragaglitazar (I) defined below is known to lower sugar level, lower total cholesterol (TC); increase high-density lipoprotein (HDL) and decrease low-density lipoprotein (LDL), which have a beneficial effect on type-II diabetes, coronary heart disease, and atherosclerosis.