The Baker-Venkataramn transformation using NaOH in dimethylsulphoxide (DMSO) 77 have been employed for the coversions of ester (o-aroyloxy/ heteroaroyloxyacetophenones) into the corresponding bis β-diketones. A novel class of 2, 8-bis(aryl/heteroaryl) pyrano [3, 2- γ] chromene-4, 6-diones have been synthesized. Bis- β diketones obtained undergoes cyclisation to achieve 2, 8-bis(aryl/heteroaryl) pyrano [3, 2- γ] chromene-4, 6-diones with impressive yields. Reaction mechanism for their formation have been elucidated. 4, 6- Diacetylresorcinol was obtained by the acylation of resorcinol. The structures of these compounds were confirmed by IR, NMR and Mass spectral studies