Empirical solvatochromic polarity parameters ( a-, b-, and p*, AN and DN, as well as E T (30)-values) for cellulose, N,N-dimethylacetamide (DMA)/LiCl and cellulose dissolved in DMA/LiCl are presented. The following solvent polarity indicators were applied: 2,6-diphenyl-4-(2,4,6-triphenyl-1-pyridinio)-1-phenolate ( 1), bis(4-N,Ndimethylamino)-benzophenone (MK, 2), iron(II)-di-cyano-bis(1,10)-phenanthroline, Fe(phen) 2 (CN) 2 , (3), and copper(II)-N,N,N ,N-tetramethyl-ethylendiamine-acetylacetonate tetraphenylborate/chloride/bromide (Cu(tmen)(acac) / X 0 (4). The solvatochromic shifts (n max ) of the indicators 1, 2, 3, and 4 adsorbed to cellulose or dissolved in DMA/LiCl reflect the corresponding properties of the surrounding, the dipolarity/ polarizability (p*), the hydrogen bond donating ability or Lewis acidity (a), and the hydrogen bond accepting ability or Lewis basicity ( b), respectively. Any indicator employed is well characterized ( r ΓΊ 0.97) by a linear solvation energy relationship (LSER) taking the Kamlet and Taft parameter into account: n max (indicator) Γ
n max,0 / sp* / aa / bb. Cellulose, DMA/LiCl, and the cellulose/DMA/LiCl solution approach a similar polarity with an E T (30) parameter about 52 to 53 kcal mol 01 . The hypothetical interaction strength parameter (acid-base interactions, dipolar-dipolar interactions) between cellulose and DMA/LiCl are calculated by means of the individual Kamlet-Taft parameters a, b, and p* of cellulose and DMA/LiCl via a multiparameter equation. The specific chloride/cellulose interaction plays a dominant role in the cellulose solvent DMA/LiCl. Comparison of the polarity parameters of DMA/LiCl with the polarity parameters of other mixtures-such as N,N-dimethyl-formamide/LiCl, DMA/NaCl, or DMA/LiBr-are presented as well.