Individually, ferrocene and thiophenes have incredible properties and important applications. During the last two decades, scientists synthesized polythiophenes containing ferrocene in the main and side chains. Polythiophenes have redox, conducting, and optical properties. Because of these properties, polythiophenes have been used in sensing applications. In addition, ferrocene has reversible redox properties and accordingly has been used in a lot of sensing devices, such as glucose sensing. Ferrocene can have +2 or +3 oxidation state, which can correspond to “0” and “1”, and thus can be used as a memory storage material. When these two moieties are combined together, they show good compatibility. Therefore, the resulting materials/polymers have been used in memory storage and chemical sensing devices. Thus, we carefully selected studies that are only associated with ferrocene-based polythiophenes. In this review, we tried to focus on the synthesis and applications of ferrocene-based polythiophenes. There are many methods for the polymerization of thiophenes. Here, we discussed the electrochemical polymerization, oxidation polymerization, nickel mediated coupling reactions, and Suzuki polycondensation. In addition, polythiophenes can be decorated with ferrocene, pre- or post-polymerization. These materials were examined for important applications, including information storage, DNA sensing, protein sensing, and glucose sensing materials.