A cost-effective and eco-friendly, straightforward synthesis of highly diversified a novel class of benzo[d]imidazo[2,1-b]thiazol-3-yl)-2H-chromen-2-one scaffold is successfully achieved via one-pot three-component cascade reaction utilizing 2-aminobenzothioazole, arylglyoxal monohydrate and 4-hydroxycoumarin in ethanol–PEG-600. Tedious work-up procedures, column purifications are avoided because of the direct precipitation of products from the reaction solution.