Because of its ability to form stable complexes with a wide variety of metal ions, cyclam (1,4,8,11-tetraazacyclotetradecane) is one of the most studied ligands in coordination chemistry. Functionalizing the cyclam unit with photoactive dendrons open a door to construct giant homo- and heteroleptic metal complexes that display interesting spectroscopic properties, particularly as far as luminescence is concerned. Light is a tool both to study metal coordination processes, and to act as input or output in order to achieve the desired function.This paper reviews some results obtained with metal complexes of cyclam-based dendrimers capable of acting as: (i) sensor, (ii) logic gates, and (iii) molecular antennae.