Chemical demulsification is the most extensively used method for breaking water-in-diluted bitumen emulsions in oil sands processing. In this paper, the properties and performance of three demulsifier formulations and their individual EO-PO polymer components were studied. The EO-PO polymers and demulsifier formulations were characterized by their relative solubility number (RSN). The results showed that the RSN is an additive property. The dehydration efficiency of the demulsifier formulation was higher than the individual components at the same dosage, signifying that there were collaborative interactions among the polymers on mixing. Correlations between performance of the demulsifiers and interfacial tension (IFT), yield stress of underflow, and bitumen loss to tailings were investigated. The results showed no correlation between the performance of the demulsifiers and equilibrium IFT. Correlations were observed between dehydration efficiency and both yield stress of the underflow and bitumen loss to tailings. The yield stress of the underflow, which included settled solids, water, and a rag layer, increased with increasing dosage of either component or demulsifier formulation. In addition, the bitumen loss to underflow increased with increasing dosage of either component or demulsifier formulation. The yield stress and bitumen loss to underflow decreased on mixing the components. The bitumen loss to underflow increased the size of the aggregates present in the underflow, increasing their immobility and constriction to flow and eventually leading to higher yield stress.