<p>The increasing demand for energy has sparked interest in the development of sustainable cost-effective materials for electrochemical energy conversion devices such as fuel cells and solar cells. Since the performance of these devices depends greatly on their electrode and electrolytic components, enormous efforts have been devoted in the direction of fabricating these components from biopolymers and it becomes an interesting area of research. In this review, we particularly focus on the utility of biopolymer-derived electrode and electrolyte components (biopolymer components, BPCs) and their impact on the performance of two major energy conversion devices namely fuel cells and dye-sensitized solar cells (DSSCs). The functional features of biopolymers, properties, and their applications in DSSCs and fuel cells are summarized. Besides, various modification strategies adopted to upgrade their physico-chemical properties and their benefits with a primary focus on the device performance are emphasized. Ultimately, this review highlights the future possibilities of BPCs in three distinct realms: (i) design and development of exceptionally efficient components, (ii) fabrication of sustainable and economically viable energy conversion devices, and (iii) optimization of operational parameters for real-world applications. In light of this, the review will provide guidelines for the development of BPCs for the production of sustainable and economically viable energy conversion devices with the goal of delivering affordable clean energy to the society.</p>