The crossed beams reaction of the phenyl radical (C6H5) with 1,2-butadiene (CH3HCCCH2) was studied under single collision at two collision energies. The crossed beams data were combined with electronic structure calculations on the C10H11 potential energy surface. The reaction was found to follow indirect scattering dynamics via an addition of the phenyl radical with its radical center to the sterically favorable C1 atom of the 1,2-butadiene reactant. The initial reaction intermediate decomposed via atomic hydrogen loss to form two C10H10 isomers, 1-phenyl-3-methylallene (p1) and 1-phenyl-butyne-2 (p2), via tight exit transition states. The results are compared with the crossed beams study of phenyl radicals with a second C4H6 isomer, 1,3-butadiene. Published by Elsevier B. V.