The development of optical sensors for in-situ, real-time and low-cost monitoring of heavy metal ions is a tremendously and fast growing area of research. This work presents several novel sensing strategies for developing optical chemical sensors that can be used as early warning devices for heavy metal pollution in water. The optical sensors that are comprised of metal chelating reagent, together with an ion carrier immobilised within polymeric thin films, i.e. hybrid sol-gel thin films, PVC membranes, ORMSOLs, and functionalised cellulose membranes. The developed test strips based on 2-(5-bromo-2-2pyridydylazo)-5-diethylaminophenol (Br-PADAP) immobilised on hybrid nafion/sol-gel membranes are capable of selectively monitoring Ni2+ in water samples. A novel sensing strategy, based on electrostatically immobilisation of water soluble indicators on functionalised cationic cellulose membranes, has provided a real “green” procedure for the fabrication of sensing materials. The promising results have been demonstrated by the optical sensor based on Chromoazo S immobilized on cationic cellulose membranes for the determination of Cu2+. A novel series of double armed spirocyclic calix[4]arene compounds has been investigated for their binding abilities with heavy metal ions. Compound 2-144 showed a good selectivity of Pb2+ over other heavy metal ions. This compound has a potential for the use as selective-ionophore for the development of a Pb2+ selective sensing system.