This article aims to review the recent progress and future aspects of organic solar cells (OSCs). Different device designs proposed for efficient light harvesting and their advancements have been discussed. We have discussed various parameters limiting their efficiency and their possible solutions. Special attention has been paid to understand the device physics and its fundamental facets. Open circuit voltage (Voc) is an important parameter in the determination of their efficiency, but the picture behind the real origin of Voc is not very much clear; therefore, this issue has been discussed in detail. Short lifetime is another important issue; therefore, recent progress in stability and related issues has also been discussed. The progress in roll to roll (R2R) processing and demonstration for large-area OSCs has been paid particular attention. The areas, where further advances will help in the commercial realization of this technology, have also been discussed. Copyright © 2011 John Wiley & Sons, Ltd.