‘Sensornets’ are large-scale distributed sensing networks comprised of many small sensing devices equipped with memory, processors, and short-range wireless communications capabilities.1 These devices, assembled from building blocks known as ‘Motes’ can gather and share sensor data from multiple locations through in-built wireless communications capabilities. The vision of incorporating chemical and biological sensing dimensions into these platforms is very appealing, and the potential applications in areas critical to society are truly revolutionary.2 For example, the environment; sensors monitoring air and water quality will be able to provide early warning of pollution events arising at industrial plants, landfill sites, reservoirs, and water distribution systems at remote locations. The crucial missing part in this scenario is the gateway through which these worlds will communicate; how can the digital world sense and respond to changes in the real world? Unfortunately, it would appear from the lack of field deployable devices in commercial production that attempts to integrate molecular sensor science into portable devices have failed to bear the fruits promised; this problem is what we call ‘the chemo-/ bio-sensing paradox’.3 In this work, we shall discuss how sensors and sensing systems are likely to develop in the coming years, with a particular focus on the critical importance of new concepts in fundamental materials science to the realisation of these futuristic chemo-/bio-sensing systems. This work focuses on the fundamental challenges, such as the ability to control the characteristics and behaviour of polymers and fluids, and processes occurring at solid-liquid interfaces. We will highlight the key role that stimuli-responsive materials can play in producing new “adaptive” materials capable of exhibiting dramatic changes in properties by external stimuli, such as, photon irradiation.4 In particular, the photochromic processes of spirobenzopyran, figure 1. These materials have the potential to revolutionise the way we design chemical and biological sensing systems.