These sensors, however, exhibit limitations with regard to the required high operation temperatures and lack of selectivity for different gases. Organic semiconductors have therefore been used to overcome such limitations [8], as they are advantageous due to room temperature operation, short response and recovery times, facile fabrication and high sensitivity. Among the organic semiconductors used for gas sensing are included metal phthalocyanines (MPcs),porphyrins, pentacene, etc. MPcs, in particular, are of most