A series of 5-chloro-N-aryl-1H-indole-2-carboxamide derivatives were prepared and evaluated as inhibitors of human liver glycogen phosphorylase a (hLGPa). One compound, 5-chloro-N-[4-(1, 2-dihydroxyethyl) phenyl]-1H-indole-2-carboxamide (2f), inhibited hLGPa with an IC50 of 0.90 μM. The pyridine analogue of 2f showed inhibitory activity of glucagon- induced glucose output in cultured primary hepatocytes with an IC50 of 0.62 μM and oral ...