Experiments on 1ID2 suggest that the imidazoliumflipped acid form is more stable than the unflipped form by about 1 kcal/mol, in solution at T = 297 K. Focusing on 1ID2, the conventional PCM with ε s = 78.4 is closest to that experimental value, predicting that the flipped from is 1.75 kcal/mol more stable, although the two HetPCM methods predict that the flipped form is 2.0-2.5 kcal/mol more stable, which is much closer to experiment than the gas-phase value (4.9 kcal/mol more stable).