Twenty benzimidazole derivatives bearing in position 1 a ( $$\omega $$ -tert-amino)alkyl chain (mainly quinolizidin-1-ylmethyl) and in position 2 an aromatic moiety (phenyl, benzyl or benzotriazol-1/2-ylmethyl) were evaluated at the National Cancer Institute (NCI) for anti-proliferative activity against a panel of 60 human cancer cell lines. Four compounds (6, 7, 9 and 10) displayed a large spectrum of activity with $$\text{ GI }_{50}<$$ 10 $$\upmu \text{ M }$$ on 24–57 cell lines, while thirteen compounds exhibited sub-micromolar or even nanomolar activity against single cell lines, such as leukemia CCRF-CEM, HL-60 and MOLT-4, CNS cancer SF-268 and, particularly, renal cancer UO-31, sometimes with outstanding selectivity (compounds 5-7, 11, 13 and 18).