Among all renewable sources, solar energy is the crucial zero emission renewable energy and the amount of solar energy impinging upon earth surface in one hour far exceeds the annual global energy demands. Polymer solar cells research exceeds crystalline silicon solar cells due to being inexpensive, light weight and processable into large area flexible devices. Polymer solar cells also possess high potential for power generation applications in comprehensive non-grid and grid modes. Moreover, the broad installment of polymer solar cells across the globe would certainly help to solve the problems associated with pollution, non-renewable resources, global warming and sustainability. Polymer solar cells being at present the hottest field of interdisciplinary research, there has been remarkable outcome in terms of efficiency of single-junction polymer solar cells, tandem solar cells, polymer-polymer solar cells, triple-junction polymer solar cells and solution-processed polymer solar cells. The present review briefly provides the latest breakthroughs and developments towards the efficiency and commercial aspects of various polymer solar cells.