The invention provides extended bisphosphonate-based metal complexes using benzene1,4-bis(bisphosphonic acid) (BBPA), an analog of benzene 1,4-dicarboxylic acid (BDC). Hydrothermal synthesis of BBPA with the bioactive metals Ca2+, Zn2+, and Mg2+ leads to four crystals phases, namely, BBPA-Ca forms I and II, BBPA-Zn form I, and BBPA-Mg form I. Out of the three structures, BBPA-Ca form II presents large channels (8 Å×12 Å), potentiating the use of this framework to load drugs. Cytotoxicity effects of BBPA was elucidated in a human breast cancer MDA-MB-231 and a normal osteoblast hFOB 1.19 cell lines. The half-maximal inhibitory concentration (IC50) for BBPA used to treat both cell lines were >200 μM at 24, 48, and 72 h of treatment. The BBPA in the range of concentration employed (0-200 μM) was not cytotoxic against these cell lines.