Metal free selective C-Se cross dehydrogenative coupling strategy has been established. The disclosed protocol unites structurally complex molecular hybrids with phenylselenol to sp2 carbon with complete regioselectivity to foster novel phenylseleno-substituted hydrazonoindolin-2-one hybrids. The product was achieved via C-H activation path and was impossible without transition metal catalysts till date. Herein we have achieved unification via Cross dehydrogenative Coupling in PEG-400 with sonication synergistic effect which sets new and easy method to achieve such a difficult path through easy reaction route. The simple reaction setup with PEG-400, a green and inexpensive catalyst solvent system, sonication a green energy source, suitable reaction time, better product yield serves as a complete green compendium to achieve metal free C-Se coupling reaction. Hence the reported methodology will act as a base for designing routes for other important molecular hybrids using green synergy of sonication and PEG-400.