  QCD instantons are known to produce deeply bound diquarks. We study whether
it may be used as building blocks in the formation of multiquark states, in
particular pentaquarks and dibaryons.
  A simple model is presented in which the lowest scalar diquark (and possibly
the tensor one) can be treated as an independent ``body'', with the same color
and (approximately) the same mass as a constituent (anti)quark. In it a new
symmetry exists between states with the same number of ``bodies'' but different
number of quarks appear, in particular the 3-``body'' pentaquarks can be
naturally related to some excited baryons. The limitations of this model are
seen from the fact that it leads to light dibaryon $H$. Another reported work
is based on a calculation of a large set of correlation functions for nonlocal
operators with 4 to 6 light quarks in the Random Instanton Liquid Model (RILM).
  The effective interaction between diquarks is studied and found to posses a
strongly {\em repulsive core}, due to the Pauli principle for quark zero modes.
