Over the past three decades, dye-sensitized solar cells (i. e. Gratzel cells) have evolved from a pioneering concept of molecular photovoltaics to large-scale industrial deployment. In this review article, we provide a historical overview of the developments with a focus on the scientific advancements that have set the stage for this technology to emerge and thrive. This involves insights into the (photo)electrochemistry of the underlying processes, molecular engineering of dyes, redox shuttles, and hole-transporting materials, as well as their implementation into solar cells. We further outline applications and future perspectives, involving the long-lasting objective to develop efficient solid-state alternatives to conventional dye-sensitized solar cells.