We report the synthesis of four novel monoquaternary salts and four fused pyrrolo-phenanthridine compounds, fully characterized by NMR, FT-IR, and mass spectrometry. Guided by theoretical predictions, including molecular docking studies, we assessed their cytotoxic activity and biocompatibility. The docking results revealed notably stronger binding affinities compared to Phenstatin, a known anticancer agent, suggesting high therapeutic promise. In vitro cytotoxicity was evaluated on osteosarcoma cell lines HOS and MG-63, showing a marked cell-line-dependent response: all compounds inhibited MG-63 cell viability by approximately 50%, while their effect on HOS cells was more modest (20%-30%). No significant activity was observed against the MeWo melanoma line. Nonetheless, compounds 3a-d, 5a, and 5b demonstrated good biocompatibility at 10 and 50 µM and selective cytotoxicity toward MG-63 cells. These findings, combined with favorable docking profiles, highlight the potential of these compounds as anticancer candidates and justify further investigation.