Porphyrins are tetrapyrrolic macrocycles with a fascinating and multifarious variegation of properties of essential significance
in up-to-date and leading technologies. This class of compounds exhibits very attractive properties as for well established synthetic paths,
advantageous photophysical characteristics, high sensitivity, selectivity, response and recovery times, and reproducibility in sensors. Porphyrins
solution, porphyrin-based nanocomposites and porphyrin Langmuir–Blodgett films porphyrins in membranes as sensors for metal
ions, gas, explosives, amine, acid, DNA and others has been reviewed in spectrophotometric (absorption, light scattering and fluorescence),
electrochemical or chromatographic methods.