  Supersymmetric (SUSY) models and dynamical breaking of symmetries have been
used to explain hierarchies of mass scales. We find that a chiral
representation, $\overline{\bf 10}\, \oplus\, \overline{\bf 5}\, \oplus\,
2\cdot{\bf 5}$ in SUSY SU(5) in the hidden sector, breaks global SUSY
dynamically, by producing a composite field $\phi$ below the SU(5) confinement
scale. This dynamincal SUSY breaking can have two important applications, one
in particle physics and the other in cosmology. Gavitational effects transmit
this dynamical breaking to the standard model(SM) superpartners and the
quintessential vacuum energy. The SM superpartners feel the effects just by the
magnitude of the gravitino mass while the smallness of the quintessential
vacuum energy is due to the composite nature of a singlet field $\phi$. The
composite $\phi$ carries a global charge which is hardly broken in SUSY and
hence its phase can be used toward a quintessential axion for dark energy of
the Universe.
