Using high concentration biochemical assays and fragment-based screening assisted by structure-guided design, we discovered a novel class of Rho-kinase inhibitors. Compound 18 was equipotent for ROCK1 (IC50= 650 nM) and ROCK2 (IC50= 670 nM), whereas compound 24 was more selective for ROCK2 (IC50= 100 nM) over ROCK1 (IC50= 1690 nM). The crystal structure of the compound 18–ROCK1 complex revealed that 18 is a type ...