Traditionally, new material-based technologies evolve first through chemistry and physics, with device engineering assuming a key role only towards commercialization. The device structure of an OLED pixel in any screen is a testament to the contribution of engineering to the challenge of achieving efficient and stable devices. In the talk, I will discuss two fields where this is yet to happen. The first is the organic electrochemical transistors, and the second is the solution-processed organic solar cells. Using both a detailed 2D chemical-physics semiconductor device model and a rate-equation level model, I will delve into the physics and electrochemistry of OECTs showing the role of electrode reactions and counter ions. In the context of OPVs, I will show that focusing on the performance at the maximum power point, instead of the short and open circuit, allows the design where the device contributes to charge generation and extraction.