Physico-chemical complex systems are composed of many non-linearly interacting components, operate away from thermodynamic equilibrium, are adaptive to their environment, and often organize into patterns. Understanding the principles that govern such systems might lead to better understanding of life and to new types of technological applications. This contribution describes a bottom-up approach to studying complex systems, in which they are "synthesized" from smaller subunits and properly tailored interactions; the "synthesis" is guided by a set of heuristic design rules. This approach was used to develop a class of dissipative complex systems based on magnetic and hydrodynamic interactions. Some of the designed ensembles were the basis of successful microfluidic and mechanical devices. (C) 2004 Elsevier Ltd. All rights reserved.