A molecular connectivity model of the crystal densities and specific r
otations of some natural amino acids and of the longitudinal relaxatio
n rates of some natural amino acids and cyclic dipeptides is presented
. While crystal densities and relaxation rates are better described by
a set of three valence molecular connectivity indices {D-upsilon, (0)
X(upsilon), (1)X(upsilon)}, specific rotations are better described by
a set of two simple molecular connectivity indices ((1)X, (0)X). Rela
xation rates are, also, well described by the simple molecular connect
ivity (D, (1)X) index set. Use of orthogonal indices, derived from the
corresponding ordinary indices shows, in the case of specific rotatio
ns, the possibility to condense the information by the aid of a single
high quality descriptor underlining, thus, the versatility of these i
ndices and also their dependence on the orthogonalisation process.