Dislocations at grain boundaries in semiconducting two-dimensional transition-metal dichalcogenides have been found to be the origin of substantial intrinsic magnetic moments. Here, we introduce a first-principles study by Yakobson and co-workers, published in this issue of ACS Nano that shows the influence of grain-boundary tilt angle and doping level on the resulting magnetic moments. This specific property may help in designing new two-dimensional magnetic semiconductors.