To get an electromagnetic counterpart, you need matter to be in the system. It may be possible for binary neutron star and some neutron-star black hole mergers. These types of mergers are one of the predicted sources of short gamma ray bursts, so if we get reasonably lucky it may be possible to find one in coincidence. Gamma ray burst are beamed, however, so to detect it, it would have to be point towards the earth, and many of the gamma bursts that we have accurate distance measurements for are currently outside our sensitivity range. We only have estimates for a fraction of GRBs though. Lower energy EM radiation may be possible to see as well with these mergers.