Two-photon absorption (2PA) is a non-linear optical phenomenon with broad scope of applications. It has already been applied, or is under intensive investigation, in fields such as: optical limiting, multiphoton pumped frequency-upconversion lasing, polymerization-microfabrication, 3D-data storage, two-photon excited fluorescence etc. Recently we have discovered and optimized the first practical synthesis of non-fused pyrrole[3,2-b]pyrroles via domino reaction of aldehydes, primary amines, and butane-2,3-dione. Six bonds are formed in heretofore unknown tandem process, which gives rise to substituted pyrrole[3,2-b]pyrroles – the ‘missing link’ on the map of aromatic heterocycles. Unparalleled simplicity and versatility of this one-pot reaction, non-chromatographic purification and superb optical properties (including strong violet, blue or green fluorescence both in solution as well as in the solid state), brought these molecules from virtual non-existence to the intensively investigated area functional π-systems. There are four basic advantages of pyrrole-based heteroacenes over their analogs comprised of thiophene and furan. 1) The smaller radii of nitrogen atoms results in more concise assembly of the molecules. 2) The NH-π interactions assure bidirectional electronic coupling between the molecules. 3) Pyrrole is a better electron-donor, which can lead to better p-type organic semiconductors. 4) The nitrogen in pyrrole (in contrast to oxygen in furan or sulfur in thiophene) can be functionalized, which enables the introduction of additional groups controlling polarity and/or solubility. The parent 1,4-dihydro-pyrrolo[3,2-b]pyrroles served as building block to construct various π-expanded analogs including diindolo[2,3-b:2',3'-f]pyrrolo[3,2-b]pyrroles. These previously unknown ladder-type heteroacenes were synthesized in just two steps from aromatic amines, 2-nitrobenzaldehydes, and biacetyl. These compounds constitute the most electron-rich ladder-type heteroacenes known to date - EHOMO was located at (−4.6)-( −5.1) eV. Strongly fluorescent diindolo[2,3-b:2',3'-f]pyrrolo[3,2-b]pyrroles represent the longest ladder-type heteroacenes and the only existing compounds bearing the 1,4,5,8-tetrahydropyrrolo[3,2-b]pyrrolo[2',3':4,5]pyrrolo[2,3-d]pyrrole core. Two-photon absorption cross-sections of these and analogous quadrupolar dyes derived from pyrrolo[3,2-b]pyrroles, were large, especially given simplicity of the structure and only partial overlap of π-orbitals. These synthetic advancements combined with record high electron–density, close to unity fluorescence quantum yields, strong fluorescent in solid state and non-linear optical properties makes both 1,4-dihydropyrrolo[3,2-b]pyrroles and its π-expanded analogs the molecules of choice for photonics of the next decade. In conclusion its favorable combination of optical properties and electron-rich character makes it an ideal platform for many photonics-oriented challenges of modern technology-driven society.