7-Azaindole and its derivatives have been extensively investigated for uses in biological probes and imaging. In contrast, there have been very limited studies on the coordination chemistry and the applications of 7-azaindole and derivatives in materials science and in chemical bond activation. Our recent research has shown that 7-azaindolyl and derivatives are excellent blue emitters for organic light emitting diodes, they have rich coordination chemistry with both main group elements and transition metal ions, and their metal complexes display not only phosphorescence but also unusual and often unprecedented reactivity toward C-H and C-X bonds. This critical review discusses recent advances in these fields with focuses on new 7-azaindolyl derivatives and their metal complexes developed by our group. The luminescent properties and applications of 7-azaindolyl-based compounds will be presented. The reactivity of Pt(II) complexes toward C-H and C-X bonds, especially the steric impact of the bis(7-azaindolyl) chelate ligands and bimetallic cooperativity will be discussed (86 references).