Design and simulation are becoming increasingly important as organic and printed electronics evolve into more complex systems. The process spans device, circuit and system levels. Key elements include accurate device models for printed electronics. Process Design Kits (PDKs) from manufacturers are crucial to enable effective third-party circuit design. Challenges include the need to characterize and extract the parameters of a large variety or materials and formulations, to enable accurate device-level simulations of sensors, actuators, transistors, etc.