The book offers insight into applications and developments of N4 macrocycles complexes in biomimetic electrocatalysis, electroanalysis and energy storage. Chapters are devoted to (i) the chemistry, electronic and electrochemical properties of porphyrin and phthalocyanines and their applications in analytical, photoelectrochemical and energy storage molecular devices, (ii) the use of electropolymerized porphyrins, phthalocyanines and related complexes as electrocatalysts for the activation and the detection of a wide variety of environmentally polluting and biologically relevant molecules, and (iii) the structural, theoretical and spectral characterisation of various organisations and assemblies of porphyrins and related complexes. The exploration of these fields of research is now intensely stimulating the significant developments in molecular devices and "intelligent organized materials" for sensor science and technology.