The invention relates to a compound of Formula (I) : Formula (I), or pharmaceutically acceptable enantiomers, or salts thereof. The present invention also relates to the use of compounds of Formula (I) as selective inhibitors of indoleamine 2,3-dioxygenase. The invention also relates to the use of the compounds of Formula (I) for the treatment or prevention of diseases cancer, infections, central nervous system disease or disorder, and immune-related disorders, either as a single agent or in combination with other therapies.