Biological chemosensory systems utilise the principle of combinatorial selectivity. Standard electronic nose models incorporate this principle with an array of cross-selective sensors matched with a machine- learning algorithm. A variety of sensor technologies may be utilised such as metal oxide gas sensors, conducting polymers, 2-D materials, electrochemical sensors, and others. The most glaring problem is that most sensor arrays used for electronic noses have highly correlated responses – the selectivity of individual sensors is very broad, hence the arrays are limited in terms of discrimination of large numbers of odorants. In contrast with e-noses relying on chemical sensors, bio-electronic noses benefit from the naturally optimized molecular affinities and intrinsic sensitivities of bioreceptors towards odorants. Here we focus on Odorant binding proteins (OBPs) which are small water-soluble polypeptides found in the secretory glands and in the sensory organs of insects and vertebrates. Utilizing OBPs, we show how an array of diverse odour sensors can be achieved. We demonstrate that the combinatorial concepts can be applied to these bioelectronic “noses”, and the odorant proteins can be modified by single point mutations of the binding pocket to give affinity to non-native ligands. Systems capable of detection of diverse chemicals can be easily produced.