The viscosities at 293 K (Table ) range from 57-33980 mPa-s, but most of the mixtures have viscosities between 1000-3000 mPa-s. To the authors knowledge, only three of the mixtures in Table have been utilized in DES or eutectic mixtures prior to this study. Therefore, it is impossible to make direct comparisons with similar mixtures, but the viscosities in Table are higher than those reported for ChCl based DES. Comparison of the viscosities for 1:2 TBACl vs. TBABr vs. TEACl: (+)-diethyl-L-tartrate and 1:2 TBACl vs. TBABr vs. TEACl: dimethyl-Dmalate shows that higher water content corresponds to lower viscosity. The effect of water content on the viscosity of these liquids in Table is much larger than on the density. It is also interesting that the 1:2 TBACl, TBABr, and TEACl: dimethyl-D-malate have viscosities in the 100's mPa-s, which is an order of magnitude less viscous than the other ionic mixtures in Table . Comparison of 1:1 vs. 1:2 TBACl: (+)-diethyl-L-tartrate shows that the higher mole fraction of TBACl (1:1) corresponds to a higher viscosity, even though it has higher water content. The three high viscosity mixtures (>13000 mPa-s) all have the highest ratio of TBACl, ³ 2:1 TBACl: HBD, which indicates that there is a correlation between TBACl and viscosity. dimethyl-D-malate and 1:2 TBACl vs. TBABr vs. TEACl: (+)-diethyl-L-tartrate, respectively. As shown in Table , 1:2 TBABr: HBD has the highest viscosities, but also has the lowest water content. Figure shows a comparison of the viscosities of 1:2 TBABr vs. TBPCl: (R)-methyl mandelate, and the TBABr-based mixture has the higher viscosity. However, as shown in Table , the water content is very similar, 9 vs. 10 mole percent, for these two mixtures.