The invention relates to thienopyrimidinediones of formula (1): in which R<;SUP>;1<;/SUP>;, R<;SUP>;2<;/SUP>;, R<;SUP>;3<;/SUP>;, Q, and Ar are defined in the specification. The invention also relates to processes for the preparation of the compounds of formula (1), pharmaceutical compositions containing these compounds, and use of these compounds in therapy, in particular in immunosuppression therapy.