Coumarin-Picolinohydrazone derived Schiff base as fluorescent sensor(OFF-ON) for detection of Al3+ ion: Synthesis, Spectral and theoretical studies

•New coumarin based Schiff base (7MIZ) acted as fluorescent sensor for detection of Al3+ ion among different metal ions (chloride salts) with high selectively.•Showed fluorescence turn ‘ON’ behavior of aluminium ion when it interacted with the probe.•Job's plot, binding constant value and LOD value were calculated between probe (7MIZ) and Al3+ ion.•DFT studies (B3LYP and M06-2X level of theories) were carried out to establish the interaction between probe (7MIZ) and Al3+ ion.