A series of new "hybrid compounds", Mannich base derivatives of planar polycyclic/heterocyclic starting materials, was designed and synthesized. The structures of the compounds were confirmed by spectroscopic methods and elemental analysis. Cytotoxicity of compounds was investigated in three cancer cell lines (PC3, HeLa, and MCF7) and one non-tumoral cell line (293 HEK). We tested the DNA-intercalating capability of the molecules by ethidium bromide (EtBr) fluorescence displacement experiment. Compounds' alkylation potency was investigated via in vitro incubation test using 2-mercaptoethanol, a biomimetic nucleophile. The five of the compounds (7s, 9d, 10b, 11b, 12c) are reported for first time in the literature. Our results suggest that compound 9d has a biological activity close to the reference compound doxorubicin, an intercalating agent in clinical use.