New chiral camphane-derived benzisoselenazol-3(2H)-ones and corresponding diselenides have been synthetized using a convenient one-pot procedure. Se-N bond was efficiently converted to an Se-Se bond, which could also be easily re-oxidized to the initial benzisoselenazolone moiety. The antioxidant activity of camphor derivatives was evaluated and compared to the reactivity of a series of N-amino acid benzisoselenazol-3(2H)-ones obtained by a modified procedure involving the improved synthesis and isolation of the diseleno bis(dibenzoic) acid. The most efficient peroxide scavengers, N-bornyl and N-leucine methyl ester benzisoselenazol-3(2H)-ones, were further evaluated as cytotoxic agents on four cancer cell lines (MCF-7, HEP G2, HL 6, and DU 145) and normal cell line PNT1A. The highest antiproliferative potential was evaluated for two compounds bearing a 3-methylbutyl carbon chain, N-leucine methyl ester and N-3-methylbutyl benzisoselenazol-3(2H)-ones.