Unsymmetrical Bis‐Coumarin Based on o‐Hydroxy Aldehydes and 4‐Hydroxy Coumarin: Expedient Synthesis, Single Crystal X‐rays and DFT Studies. - Das, Barnali; Paul, Abhijit Rudra; De, Utpal C.; Paul, Bhaswati; Natarajan, Ramalingam; Chakraborty, Sourav; Majumdar, Swapan (ChemistrySelect, 2023)