Miniaturization of coordination polymers to the nanoscale represents a unique opportunity to assemble a novel class of highly customizable functional materials that marry the rich diversity, chemistry and properties of coordination complexes to the advantages of nanomaterials. The new structures, which exhibit well-defined and dispersed morphologies, can allow for a proper correlation with their functionality, and therefore, enable the rational design of new generations of these nanostructures targeting specific desired properties. In this chapter we will give a brief introduction to the rational fabrication of such functional nanostructures following different coordination polymerization mechanisms. The novel “smart” nanoscale coordination polymer particles (NCPs) exhibit interesting properties of relevance for different fields and applications, worth to mention nanomedicine and sensors. Herein we make a summary of the main results obtained in both areas that evidence the significance of this novel family of materials. For this, the review has been divided into two main sections. In the first part we revise general methodologies for cargo loading and delivery, including the design of stimuli-responsive systems. In the second section we will review the latest advances in the use of NCPs as chemical sensing platforms. These results open new avenues for all the possible applications that can be derived from the implications of CPPs on surfaces. Finally, a brief introduction to the new research line on 2D-coordination polymers will be outlined.