The isobaric analog state (IAS) of the halo nucleus 1 1 Li has been investigated using the charge reaction 1 1 Li(p,n) 1 1 Be * in inverse kinematics at E( 1 1 Li) = 64A MeV. The IAS was observed in exchange 1 1 Be, for the first time, at an excitation energy of 21.16 ± 0.02 MeV with a width of 0.49 ± 0.07 MeV (FWHM). The unit cross section, distortion factor and effective N-N interaction associated with the Fermi transition are extracted. Coulomb displacement energy, decay width, reaction variables and their relation to the halo structure are discussed.