In ongoing studies of the two known para-aminobenzoic acid (PABA) polymorphs we discovered that near-edge X-ray absorption fine structure (NEXAFS) measurements permit determination of hydrogen bond lengths in organic crystal structures with an accuracy hitherto only achievable by neutron diffraction. Unfortunately neutron diffraction data are currently not available. We therefore propose use of single crystal neutron diffraction to determine H locations to confirm N-H bond lengths determined by NEXAFS analysis. NEXAFS is unique to each polymorph, reflecting differences in local electronic and bonding environments. We found dramatic improvements in ab initio predictions of material properties on replacing N-H bond lengths predicted by single crystal XRD with those obtained by NEXAFS analysis. The envisaged neutron diffraction would independently validate conclusions drawn from NEXAFS.