In this work libraries of morpholines and oxazepanes have been prepared via the reductive amination reaction between dialdehydes, derived from carbohydrates, and a range of amines. In this way, functionalised morpholines and oxazepanes have been prepared that include N-alkylated derivatives, disaccharide analogues, and ester containing derivatives. The abilities of these functionalised morpholines and oxazepanes to inhibit a broad panel of glycosidase enzymes, that are associated with a range of diseases, have been probed and in this way new inhibitors of a range of glycosidases, but particularly β-d-galactosidase derived from Bovine kidney, have been discovered. N-Alkyl morpholines demonstrated the best inhibition profiles for this enzyme and derivatives (15a)-(15d) acted as non-competitive inhibitors with IC(50) values of 55.1-88.6 μM. Within this study, some preliminary structure-activity relationships are proposed, and it is demonstrated that N-substituted morpholines display better inhibitory profiles for the enzymes analysed than any of the N-substituted oxazepanes.