We propose a novel class of tunable nanowires by incorporating transparent conducting oxides and active semiconductors such as Indium tin oxide (ITO) and 4H-silicon carbide (4H-SiC) into multimaterial configurations in which a continuous tunability of optical properties can be obtained via field-effect modulation by applying an external bias. These building blocks offer the opportunity to develop a new generation of metamaterials, in which the optical properties can be dynamically changed in real-time. In particular, the resonant characteristic of an ITO-integrated multimaterial nanowire is exploited to obtain a continuous tunability of transmission phase over 260 degrees which enables beam-shaping to the desire through a geometrically fixed metasurface by controlling the external bias for each element. Moreover, it is demonstrated that deeply subwavelength elements of such multimaterial configurations can yield strong variations in the effective permittivity by changing the bias voltage which can add tunability into metamaterial platforms. The field-effect modulation can also be exploited to tune the effective permeability of epsilon-near-zero nanowires which enables tuning the impedance of zero-index metamaterials. The performance of these electro-optical platforms is characterized rigorously by linking the charge transport and electromagnetic models via dispersion models. The charge transport model is governed by drift-diffusion equations while the electromagnetic modeling is carried out using a robust semi-analytical method based on transition matrix formulation which enables accurate and efficient analysis of multimaterial nanowires. The proposed tunable nanowire antennas can enable on-demand controllable meta-systems.