Recent advances in synthetic methods and analysis techniques provide a basis for the construction and characterization of organized arrays of molecular switches and motors on surfaces. Among them, molecular systems that can be controlled by light are particularly promising because of their ease of addressability, fast response times and the compatibility of light with a wide range of condensed phases. The aim of this contribution is to highlight selected recent advances in building functional monolayers of light-activated molecules. Special focus is given to monolayers of molecules whose collective switching properties have been harnessed to produce macroscopic effects. The design, structure, and function of monolayers composed of bistable photochromic switches, which can control chirality, wettability, conductivity and self-assembly are described. A recent report on the successful demonstration of light-driven rotary motors functioning while grafted on gold surfaces will also be discussed, followed by a brief conclusion. (C) 2007 Elsevier Ltd. All rights reserved.