The binary trialuminides typically crystallize with the tetragonal D0(22) (or D0(23)) structures and frequently exist as line compounds, making it very difficult to produce them as single-phase material. As a result of their low symmetry, ordered tetragonal structures, these compounds show such limited ductility at and immediately above room temperature as to find no useful engineering application. The compound Al3Ti is known to deform by ordered twinning at ambient temperature, which does not disturb the D0(22) symmetry of the lattice during deformation, but leads to only four potential deformation systems, which is insufficient for the generalized von Mises plasticity criterion. Recent research effort has moved to improving the ductility of the trialuminides by transforming their tetragonal (D0(22)/D0(23)) crystal structures into the closely-related ordered cubic L1(2) structure, in the hope that the increased number of independent slip systems in the cubic structure will enable the alloys to deform more easily. Significant ductility in compression, and measurable plastic strain on the tensile side of bend bars, have been reported, especially in Cr and Mn-modified L1(2) alloys. However, notwithstanding these hopeful signs in the L1(2) trialuminides, these cubic alloys remain uniformly brittle in tension at room temperature. At present, the brittle behaviour of the L1(2) trialuminides appears to be intrinsic to their nature, with little scope for improvement by microstructural modification. The controversy assocated with room temperature dislocation dissociation in the L1(2) trialuminides has been concluded that the superdislocations on {111} planes are APB-dissociated pairs rather than SISF-coupled partials. In attempting to identify new approaches to overcoming the brittleness of trialuminide-based alloys, it is worth noting potential advantages of multiphase alloys over single phase alloys. The development of fine duplex microstructures, by combining judicious alloying with controlled thermal or thermo-mechanical treatments, appears to offer promise for enhancing the ductility of brittle monolithic alloys. Given this evidence, it is suggested that the design and development of multiphase or duplex microstructures for trialuminide-based alloys may provide an approach of interest in providing the ductility and/or toughness of such alloys.