General procedure for the Suzuki coupling reaction of bromoselenophene with arylboronic acid

Under Ar atmosphere, a mixture of bromoselenophene (1 equiv), arylboronic acid (3 equiv for dibromoselenophenes, 4 equiv for tribromoselenophenes), Pd catalyst (0.1 equiv), sodium carbonate (1 equiv per bromine) in an oxygen-free toluene/water (1:1) solution was stirred at 120 °C for 24 h, after which the reaction mixture was cooled to room temperature. The aqueous layer was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous MgSO₄/Na₂SO₄ and then filtered and concentrated in vacuum. The product was purified by column chromatography.