In this paper, we report on a new path of ZnWO4 phase formation, synthesized by the polymerizable complex (PC) method. At 550 °C, we obtained a single phase of the ZnWO4 complex oxide. To explain the phase transformation processes, we propose a mechanism based on the coexistence of more than one amorphous phase after the pre-pyrolysis process. These amorphous metastable phases indicate a different phase formation path, which has not yet been described in the literature for multi-component oxides processed by the PC method. The formation path proposed here shows the relevance of the metastable phases in the reaction processes of complex oxides.