L002, a potent, cell-permeable, reversible, and specific acetyltransferase p300 (KAT3B) inhibitor with an IC50 of 1.98 μM, directly binds the acetyl-CoA pocket and competitively inhibits the FATp300 catalytic domain. By blocking histone acetylation, p53 acetylation, and STAT3 activation, L002 shows potential in the treatment of hypertension‐induced cardiac hypertrophy and fibrogenesis.