Neutron diffraction measurements on 6 Li/ 7 Li isotopically substituted 10 and 33 mol % *LiTFSA (lithium bis-(trifluoromethylsulfonyl)amide)-AN-d 3 (acetonitrile-d 3 ) and 10 and 33 mol % *LiTFSA−DMF-d 7 (N,N-dimethylformamide-d 7 ) solutions have been carried out in order to obtain structural insights on the first solvation shell of Li + in highly concentrated organic solutions. Structural parameters concerning the local structure around Li + have been determined from the least squares fitting analysis of the first-order difference function derived from the difference between carefully normalized scattering cross sections observed for 6 Li-enriched and natural abundance solutions. In 10 mol % LiTFSA-AN-d 3 solution, 3.25 ± 0.04 AN molecules are coordinated to Li + with a intermolecular Li + ••• N(AN) distance of 2.051 ± 0.007 Å. It has been revealed that 1.67 ± 0.07 AN molecules and 2.00 ± 0.01 TFSA − are involved in the first solvation shell of Li + in the 33 mol % LiTFSA-AN solution. The nearest neighbor Li + •••N AN and Li + •••O TFSA − distances are obtained to be r(Li + •••N) = 2.09 ± 0.01 Å and r(Li + •••O) = 1.88 ± 0.01 Å, respectively. The first solvation shell of Li + in the 10 mol % LiTFSA-DMF-d 7 solutions contains 3.4 ± 0.1 DMF molecules with an intermolecular Li + •••O DMF distance of 1.95 ± 0.02 Å. In highly concentrated 33 mol % LiTFSA-DMF-d 7 solutions, there are 1.3 ± 0.2 DMF molecules and 3.2 ± 0.2 TFSA − in the first solvation shell of Li + with intermolecular distances of r(Li + •••O DMF ) = 1.90 ± 0.02 Å and r(Li + •••O TFSA − ) = 2.01 ± 0.01 Å, respectively. The Li + •••TFSA − contact ion pair stably exists in highly concentrated 33 mol % LiTFSA-AN and -DMF solutions.