This work investigated the carbon K-edge spectrum of BrBz + , recorded following resonance ionization with two UV photons on neutral BrBz. The influence of the bromine atom on the x-ray spectrum of the BrBz + is examined together with the spin coupling of the partially vacant 1s core orbital, the partially occupied π orbital, and the partially occupied π* orbital. In particular, the partially occupied π orbital leads to relatively weak 1sC→π and 1sC*→π transitions, while the 1sC→π* transitions are observed as a first dominant peak slightly shifted to lower energy compared to corresponding transitions in the neutral BrBz, similarly to the Bz + x-ray spectrum. Our results are supported by theoretical calculations by the ROCIS-DFT method. An additional relatively intense doublet peak is observed at higher energy and is assigned to the 1sC*→σ*(C*-Br) transition of the This transition demonstrates the significant influence of the bromine atom on the x-ray spectrum of BrBz + compared to Bz + and to neutral BrBz. The calculated spectrum reproduces the experimental features, but the big challenge of accurate calculations in large molecules remains together with a need for a better understanding of the spin coupling effect.