1H-Pyrrolo[2,3-b]pyridin-4-ol has been used as a high performance polyazaindole as a novel acid fluorescent sensor with a tunable ICT effect. 1H-Pyrrolo[2,3-b]pyridin-4-ol is also used as a reactant in the design and synthesis of potent and selective azaindole-based Rho kinase (ROCK) inhibitors.