The invention relates to the inhibition of histonedeacetylase. The invention provides compounds for inhibiting histonedeacetylase enzymatic activity. The compounds for inhibiting histonedeacetylase enzymatic activity can be represented by the formulasCy-L1-Ar Y1-C(O)-NH-ZCy-L2 Ar-Y2-C(O)NH-ZCy-L3 Ar-Y3-C(O)NH-Z,wherein Cy, L1, L2, L3, Ar, Y1, Y2, Y3 and Z are as defined in theapplication.