Rational designed benzochalcone-based fluorescent probe for molecular imaging of hydrogen peroxide in live cells and tissues

•Novel fluorescent probes based on benzochalcone fluorophore were designed and synthesized.•The probes FD-1 and FD-2 exhibited satisfactory selectivity and sensitivity for discrimination of H2O2.•The probe FD-2 has faster response rate and higher sensitivity than FD-1.•The probe FD-2 showed good imaging capability in living cells and tissues with low cytotoxicity.