An approach to the design of a series of quinolinol-based indium complexes that can exhibit different optical properties is proposed. Mono-incorporated (Inq(1) and InMeq(1)), bis-incorporated (InMeq(2)), and tris-incorporated (Inq(3) and InMeq(3)) indium quinolinate complexes have been prepared. These complexes have also been characterized by X-ray crystallography. The photophysical properties of these complexes have also been examined by a combination of experimental and theoretical techniques. The indium complexes with a single quinolinol ligand (Inq(1) and InMeq(1)) showed higher quantum efficiency than those with two or three quinolinate ligands; in particular, InMeq(1) exhibited the highest quantum yield [Phi(PL) = 59% in poly(methyl methacrylate) film]. The insights into the nature of these findings were obtained by the sequential synthesis of the quinolinol-based indium luminophores and a detailed investigation of their structural stability.