Objective: In this review we present the general principles that are at the basis of the construction of
artificial molecular devices and machines and the main characteristics of these systems with a special focus for
the kind of energy inputs needed to make them work.
Methodology: By the bottom-up (chemical) approach science and technology move from micro- to nanoworld,
and due to the nature of inputs (light and chemical) they move from electronics to photonics and chemionics.
Furthermore the chemical molecule-by-molecule bottom-up approach offers unlimited opportunities for
design and construction of nanoscale supramolecular structures, by combining the high precision of the chemical
synthesis and scientists with a device driven-ingenuity. Furthermore, because the ability to perform specific
functions as a response to external stimuli depends directly on the chemical nature and properties of the component
units, in this review, we illustrate some examples of molecular devices and machines based on specific
molecular units that have been developed in the research group of one of the authors. They are systems exhibiting
pseudorotaxane, rotaxane, catenane and dendrimer structures that incorporate redox- and/or photoactive
Conclusion: The future development of this kind of research will lead to more and more sophisticated artificial
molecular devices and machines with better performances regarding their stability, switching, speed, and functions
performed. We foresee that they will find useful applications in various fields, like energy conversion,
sensoring, catalysis, and will give a great contribution in solving the present-day main problems regarding
food, health, energy supply, and environment protection.