The project team has made great advancements in synthesis, testing and simulations in Q5. The theory team has modeled the reaction mechanism of CO2BOLs, for the firs time showing a concerted CO2 attack and proton transfer, with low activation energy barriers, indicating the reaction would be diffusion limited. The simulation team also has modeled a unique acid/base equilibrium between the proton of the alkylcarbonic acid and guanidine base core. The team found that this equilibrium could be tuned to reduce charge transfer as a means to limit viscosity increases. The synthesis team has developed a superior synthetic methodology to make candidate molecules, reducing byproducts, and ultimately improving the yield, which is projected to aid in cost reduction targets required in Milestone 8. The testing team has recently met Milestone 4, but also experimentally validated what theory had predicted, that CO2BOL solvents have two liquid states; a metastable liquid and a glassy liquid. Viscosity measurements on the new PVT showed experimental evidence for two liquid states as measurements at different resonance times showed two vastly different viscosities. More detailed descriptions of each accomplishment are provided below.