We discuss the possible existence of exotic dibaryons with a heavy antiquark, being realized three-body systems, [Formula: see text] and B(*)NN. These are genuinely exotic states with no quark-antiquark annihilation. We consider the heavy quark spin symmetry and chiral symmetry, and introduce the one pion exchange potential between a [Formula: see text] meson and a nucleon N. As for the NN interaction, we employ the Argonne [Formula: see text] potential. By solving the coupled-channel equations for PNN and [Formula: see text], we find bound and resonant states near the thresholds both in charm and bottom sectors.