The series of compounds REAu2In4 (RE = La, Ce, Pr, Nd) crystallize from excess In as rod-shaped single crystals. All members adopt the orthorhombic space group Pnma with a 18.506(2) angstrom, b = 4.6865(6) angstrom, and c = 7.3414(9) angstrom for LaAu2In4, a = 18.514(3) angstrom, b = 4.6624(8) angstrom, and c = 7.389(1) angstrom for CeAu2In4, a = 18.420(4) angstrom, b = 4.6202(g) angstrom, and c = 7.376(2) angstrom for the Pr analogue, and a = 18.406(2) angstrom, b = 4.6114(5) angstrom, and c = 7.4073(7) A for NdAu2In4. The REAu2In4 series can be regarded as polar intermetallic phases composed of a complex [Au2In4](3-) polyanion network in which the rare-earth ions are embedded The [Au2In4](3-) network features In tetramer units, which defines the compounds as polyindides. Magnetic measurements found no magnetic ordering down to 2 K for any of the compounds. In addition, LaAu2In4 was found to be Pauli paramagnetic with a small susceptibility. Ab initio, density functional methods were used to carry out electronic structure calculations to explore the bonding, the role of gold, and the contributions of different atoms to the density of states near the Fermi energy. We find that the density of states decreases slowly near Et and reaches a minimum at about 0.5 eV above E-i.