New 1,5-benzothiazepin-4-(5H)-one derivatives (9a-9e) have been synthesized. The anti-angiogenic and antioxidant properties of the new derivatives were then evaluated. All the compounds (9a-9e) exhibited very good inhibition of capillary proliferation, thus proving their anti-angiogenic properties. In addition, the in vitro antioxidant activities of these compounds were evaluated using diphenyl picryl hydrazine (DPPH), and NO (nitric oxide) assays, and the results were compared with butylated hydroxytoluene (BHT), a well known anti-oxidant. Compounds (9a-9e) showed excellent free-radical scavenging activities in the nitric oxide assay, thus proving to be more potent than BHT.