Nanocrystal comprising an inorganic core consisting of least one metal and/or at least one semi-conductor compound comprising at least one metal, the external surface of said nanocrystal being provided with an organic coating layer, consisting of at least one ligand compound of formula (I): X--Y-Z (I) in which X represents a 1,1-dithiolate or 1,1-diselenoate group that is linked by the two atoms of sulphur or selenium to an atom of metal of the external surface of said nanocrystal; Y represents a spacer group, such as a group capable of allowing a transfer of charge or an insulating group; Z is a group chosen from among groups capable of communicating specific properties to the nanocrystal. Their methods of manufacture.