Completing a SAR study, a series of (RS)-1- or 3-(1,2,3,5-tetrahydro-4,1-benzoxazepine-3-yl)-pyrimidines and (RS)-6-substituted-7- or 9-(1,2,3,5-tetrahydro-4,1-benzoxazepine-3-yl)-7H- or 9H-purines have been prepared. Their antiproliferative activities on MCF-7 cells are here presented and discussed. (RS)-6-Chloro-9-[1-(9H-9-fluorenylmethoxycarbonyl)-1,2,3,5-tetrahydro-4,1-benzoxazepine-3-yl]-9H-purine (28) is the most active (IC(50)=0.67+/-0.18 microM) of the series so far described. cDNA microarray technology reveals potential drug targets, which are mainly centred on apoptosis regulatory pathway genes.