This paper presents a short review of liquid-crystalline (LC)polyimides. It is shown that it is difficult to obtain LC-polyimides free of ester groups. Only three examples of such polyimides have been found so far. LC-Poly(ester-imide)s may be subdivided into two groups. The first groups contains aliphatic spacers in the main chain and possesses a high tendency of forming layer structures in the solid state. The origin of the layer structures is discussed. The second group conprises poly(ester-imide)s with a fully aromatic main chain. The role of substituents, conformations and donor-acceptor interactions for the stabilization of nematic phases is discussed.