Uncovering new therapeutics for kidney fibrosis hold promise for chronic kidney disease (CKD). Considerable studies confirmed that BRD4 inhibition ameliorated kidney injury and fibrosis. In the study, we synthesized a series of indol-6-yl-pyrrolo[2,3-c]pyridin-7-one derivatives and biologically evaluated against BRD4 for structure-activity relationship (SAR). Notably, compound 3r (ZLD2218) exhibited the most potent inhibitory activity against BRD4, with the IC₅₀ value of 107 nM, which was comparative to 92 nM of positive control JQ-1. Importantly, at the dose of 15 and 30 mg/kg/d for consecutive 8 days, ZLD2218 alleviated kidney injury and fibrosis in unilateral ureteral obstruction (UUO) mice, with the 30 mg/kg/d being competitive to 100 mg/kd/d of JQ1. Mechanically, ZLD2218 inhibited BRD4 expression and further suppressed fibrotic signaling in the kidneys of UUO mice and TGF-β1-stimulated TCMK-1 cells. Furthermore, ZLD2218 at the dose of 30 mg/kg/d for 8 days to C57BL/6J mice did not affect liver, kidney function and organ pathological changes. Collectively, compound 3r (ZLD2218) might be a promising lead compound of BRD4 inhibitor for the treatment of kidney fibrosis.