We have attained the first sub-arc second collimation of amonochromatic neutron beam by diffracting neutrons from a Braggprism, viz. a single crystal prism operating in the vicinity of Bragg incidence. Analytical as well numerical computations based on the dynamical diffraction theory, led to the optimized collimator configuration of a silicon {111} Bragg prism for 5.26 Å neutrons. We fabricate da Bragg prism to these specifications, tested and operated it at the double diffractometer setup in Helmholtz Zentrum Berlin to produce a 0.58 arcsec wide monochromatic neutron beam. With a similarly optimized Bragg prism analyser of opposite symmetry, we recorded 0.62 arcsec wide virgin rocking curve for this ultra-parallel beam. With this nearly plane-wave neutron beam, we have recorded the first ever USANS spectrum in Q~10^-6 Å^-1 range with a hydroxyl apatite case in protein sample  and demonstrated the instrument capability to characterize agglomerates upto150 mm in size. The super-ollimated monochromatic beam has also enabled us to record the first neutron diffraction  pattern from a macroscopic grating of 200 mm period. The transverse coherence length of 175 mm (FWHM) of the ultra-parallel beam derived from the analysis of this pattern, is the greatest achieved to date for Å wave length neutrons.