The geometry and hyperpolarizabilities of 4-aminoindoaniline have been calculated by molecular orbital and density functional theories. There are two conformers for 4-aminoindoaniline for which the dihedral angle tau(C-3-C-4-N-2-C-7) differs at the MNDO/PM-3 level. Density functional theory calculations predict that the two conformers, one with tau(C-3-C-4-N-2-C-7) = 45.2 degrees (conformer B) and one with tau(C-3-C-4-N-2-C-7) = 31.5 degrees (conformer A) are isoenergetic at the nonlocal level and differ by 0.5 kcal/mol at the local level. Hyperpolarizabilities of these two conformers were calculated at the local DFT level with a double numerical basis set augmented by polarization functions (DNP) giving beta(A) = 28.9 x 10(-30) esu and beta(B) = 38.1 x 10(-30) esu. If diffuse functions are added to the heavy atoms, the values are beta(A) = 30.9 x 10(-30) esu and beta(B) = 40.1 x 10(-30) esu. The best calculated values for gamma are gamma(A) = 17.4 x 10(-36) esu and gamma(B) = 25.4 x 10(-36) esu.