o‐Bromostyrenes 2‐Br react with various alkenes in the presence of palladium catalysts to give either substituted indene 6 or o‐diethenylbenzene derivatives 3, depending on the reaction conditions. Under oxidative conditions the latter can be cyclized to indene derivatives as well.

The palladium‐catalyzed coupling of ethene with 4‐bromobiphenyl and 4′‐bromo‐4‐biphenylsulfonic acid permits a facile one‐pot preparation of the laser dyes (E)−4,4′‐diphenylstilbene (BPS, 3) and bis(triethylammonium) (E)−4,4′diphenylstilbene‐4″,4″‐disulfonate (6) in diastereomerically pure form on a multigram scale, with yields of 69 and 64%, repectively. The latter can easily be transformed to its dipotassium salt 7, the Stilbene I dye.