Pharmacological risk and economic inefficiency are some of the main shortcomings of the rapid release of drugs from nanocarriers. In the present study, relatively green, magnetic, smart dual-carrier vehicles based on pH-sensitive biopolymers, namely carboxymethylcellulose (CMC)/chitosan (CTS), have been developed to enable simultaneously controlled loading or releasing of sunitinib malate (STM) (anticancer) and saffron (SAF) bioactive compounds. Magnetic CMC (mCMC) was prepared by co-precipitation of Fe2+ and Fe3+ ions and complexation process via simple electrostatic interactions between mCMC and CTS. Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, vibrating sample magnetometry, transmission electron microscopy and scanning electron microscopy were used for characterization. The concentration of mCMC was found to be an important factor affecting the bio-nanocomposite performances. In vitro release study demonstrated higher release profiles at pH = 4.5 compared to pH = 7.4. Moreover, our data showed that the release percentage of bio-nanocomposites with a low concentration of mCMC was higher than that of bio-nanocomposites with a higher mCMC concentration. The kinetic release data were fitted using Higuchi and Korsmeyer–Peppas models. STM- and SAF-loaded mCMC/CTS demonstrated cytotoxic and antibacterial properties against MCF-7 breast cancer cells and S. aureus bacteria, indicated by MTT assay and disk diffusion method, respectively.