Sulfur-containing polymers have been widely studied because of their high refractivity and low dispersion, but the efficient synthetic approach of them is quite limited. In this work, we use the abundantly existed elemental sulfur as monomer to prepare polythioamide directly and efficiently through a facile multicomponent polymerization (MCP) of aromatic diynes, sulfur, and aliphatic diamines. This MCP can proceed smoothly in a catalyst-free manner with high atom utilization to afford polythioamide with well-defined structure, high molecular weight, and high yield. It demonstrates a convenient approach to convert elemental sulfur into functional polythioamide. Fluorescence is observed from the polythioamide, despite the absence of typical fluorophores, owing to the "heterodox clusters" composed of a large number of lone-pair-containing electron-rich heteroatoms. The emission maxima and efficiencies of the polymers depend on the formation of molecular aggregates through intrachain and intermolecular interactions such as hydrogen bonding and n → π* interaction between thioamides. This polymerization is anticipated to accelerate the development of efficient and economic MCPs toward functional polymer materials.

The study of nonconventional luminescence is important for revealing the luminescence of natural systems and has gradually drawn the attention of researchers in recent years. However, the underlying mechanism is still inexplicable. Herein, the luminescence behavior of two series of simple, heteroatom‐containing small molecules without aromatic rings, i.e., maleimide and succinimide derivatives, are studied to gain further mechanistic insight into the nonconventional luminescence process. It has been unveiled that all the molecules exhibit bright and visible luminescence in concentrated solution and solid state and the formation of clusters is the root cause for such behaviors, which can effectively increase the possibility of both the nonradiative n–π* and favorable π–π* transitions and stabilize the excitons formed in the excited state. The distinctive luminescent phenomena and intriguing mechanism presented in this work will be significant for understanding the mechanism of clusteroluminescence and provide new strategies for the rational design of novel luminescent materials.

Selenium-containing polymers are a group of fascinating functional polymers with unique structures, properties, and applications, which have been developed recently but only with limited examples. The challenges of developing selenium-containing polymers with structural and functional diversity include the lack of economic and safe monomers, lack of efficient and convenient synthetic approaches, and poor stability of selenium-involving covalent bonds. In this work, room-temperature metal-free multicomponent polymerizations (MCPs) of elemental selenium, diisocyanides, and dipropargyl alcohols were developed, and polymers with a selenium-containing aliphatic heterocycle, 1,3-oxaselenolane, were synthesized through these MCPs directly from elemental selenium. The alicyclic poly­(oxaselenolane)­s enjoyed high yields (up to 93%), high molecular weights (up to 15 600 g/mol), high thermal and chemical stability, good solubility and processability. With the structural design of the poly­(oxaselenolane)­s and their high selenium contents of up to 33.7 wt %, the refractive indices of their spin-coated thin films could reach 1.8026 at 633 nm and maintain 1.7770 at 1700 nm. It is anticipated that these efficient, convenient, mild, and economic multicomponent polymerizations of elemental selenium can promote the selenium-related polymer chemistry and accelerate the exploration of diversified selenium-containing functional polymer materials.