Polymers are considered as versatile material having number of applications. However, their properties depend upon the structure, molecular mass and its distribution and the interactions among polymer-polymer and polymer-solvent molecules. Henee it is necessary to synthesize a polymer with required specification, which is a difficult, time consuming and costly process. A highly successful alternative is to blend/ mix the existing polymers for the purpose. This process needs detail knowledge about the interactions and miscibility of polymers with each other. Therefore the objective of this study is to investigate the compatibility of polymers with reference to their concentration in the blend, using static and dynamic light scattering and Rheology of the material. For the purpose Polystyrene/ Polymethylmethacrylate, Polystyrene/Polyethylene glycol and Polymethylmethacrylate / Polyethylene glycol using benzene as common solvent systems have been investigated in detail. The variation in hydrodynamic radius with concentration of polymer in the blend is found to be a good tool to ascertain the compatibility of polymers. Viscosity results also second the light scattering observations. It has been concluded that the polymer's compatibility depends upon composition of the blend and compatible with in a certain range. The compatibility play key role in the conformational behavior of the polymers blend and the techniques used is quite sensitive to identify the phase separation point.