Synthesis, spectroscopic properties, and DFT correlative studies of 3,3′- carbonyl biscoumarin derivatives

•Photophysical properties of probes Bis-Coumarin derivatives have been investigated.•The probes are more polar in the excited state than the ground state.•HOMO-LUMO & Optical energy band gaps are in agreement with each other.•Chemical hardness studies suggest soft nature for the probes.•MESP plots exhibit both electrophilic & nucleophilic sites.