In this review, we summarize the application of porphyrins and phthalocyanines in perovskite solar cells to date.

Star-shaped magnesium porphyrins with four diketopyrrolopyrrole units conjugated by four ethynyl linkers work as electron donors for organic solar cells.

Acceptor–donor–acceptor conjugated magnesium porphyrins showed a power conversion efficiency of 5.73%, high open-circuit voltage of 0.79 V, or an extended incident photon-to-current conversion efficiency spectrum to 1100 nm, depending on the substituents.

Chromic materials, an important class of stimuli-responsive materials, have aroused extensive attention in recent years. Normally, their color is based on changes in morphology. Few examples of chromic material based on conformational isomerization, such as in overcrowded alkenes, have been reported previously. Furthemore, experimental thermodynamic studies of overcrowded bistricyclic aromatic enes have not been carried out to our knowledge. Here, we show that N-phenyl-substituted fluorenylidene-acridanes, with a properly modified fluorene moiety, performs chromisms originating from conformational changes. Thermodynamic studies determine equilibrium constants, changes in enthalpy, entropy, and free energy in solution, enabling in-depth understanding of the equilibrium behavior of overcrowded alkenes and providing useful information for designing functional chromic compounds. Single-crystal X-ray diffraction analysis of fluorenylidene-acridanes in this work clearly shows well-tuned charge transfer from the acridane to the fluorene moiety. Various chromic behaviors such as mechanochromism, thermochromism, solvatochromism, vapochromism, and proton-induced chromism also support understanding of conformational isomerism.