A compound having the structure set forth in Formula (I) and Formula (II): wherein the substituents Y, Z, A, B, R1, R2, R3, R4 and R5 are as defined herein. Provided herein are inhibitors of poly(ADP-ribose)polymerase activity. Also described herein are pharmaceutical compositions that include at least one compound described herein and the use of a compound or pharmaceutical composition described herein to treat diseases, disorders and conditions that are ameliorated by the inhibition of PARP activity.一化合物具如請求項的結構式(I)及結構式(II):其中取代基Y,Z,A,B,R1,R2,R3,R4及R5和於此所定義的相同。本篇所述為聚(ADP-核糖)聚合酶(poly(ADP-ribose)polymerase)之抑制劑。本篇亦敘述包含至少一種本篇所述的化合物之藥物成分,及本篇所述之治療疾病,不適及狀況的化合物或藥物成分之用途,及抑制聚(ADP-核糖)聚合酶(PARP)活性後狀況的改善。