Three series of azo dyes derived from 2-amino-5-aryl-1,3,4-thiadiazoles and aniline, N,N-dimethylaniline and phenol were synthesized in high yields by a conventional diazotization-coupling sequence. The chemical structures of the prepared compounds were confirmed by ¹H-NMR, ¹³C-NMR, IR, UV-Vis spectroscopy, mass spectrometry and elemental analysis. In addition, the X-ray single crystal structure of a representative azo dye was presented. For explicit determination of the influence of a substituent on radiation absorption in UV-Vis range, time-dependent density functional theory calculations were performed.

An alternative approach to the Suzuki cross-coupling reaction is used to synthesize a series of new luminophores based on 4-alkyl-4H-1,2,4-triazole cores conjugated via 1,4-phenylene linker to fused-bicyclic and tricyclic aromatic, or heteroaromatic arrangements. The described methodology allows one to conduct the coupling reaction with the use of commercially available boronic acids in the presence of conventional solvents or ionic liquids and produced excellent yields. It was found that the use of ultrasounds or microwaves significantly accelerates the reaction. The obtained compounds exhibited high luminescent properties and a large quantum yield of emitted photons. The X-ray molecular structures of three highly conjugated 4H-1,2,4-triazole representatives are also presented.

The addition of 2-amino-1,3,4-thiadiazole derivatives with parallel iodination of differently protected glycals has been achieved using a double molar excess of molecular iodine under mild conditions. The corresponding thiadiazole derivatives of N-glycosides were obtained in good yields and anomeric selectivity. The usage of iodine as a catalyst makes this method easy, inexpensive, and successfully useable in reactions with sugars. Thiadiazole derivatives were tested in a panel of three tumor cell lines, MCF-7, HCT116, and HeLa. These compounds initiated biological response in investigated tumor models in a different rate. The MCF-7 is resistant to the tested compounds, and the cytometry assay indicated low increase in cell numbers in the sub- G1 phase. The most sensitive are HCT-116 and HeLa cells. The thiadiazole derivatives have a pro-apoptotic effect on HCT-116 cells. In the case of the HeLa cells, an increase in the number of cells in the sub-G1- phase and the induction of apoptosis was observed.

New derivatives of 4-alkyl-3,5-diaryl-4H-1,2,4-triazole were synthesized utilizing the Suzuki cross-coupling reaction. The presented methodology comprises of the preparation of bromine-containing 4-alkyl-4H-1,2,4-triazoles and their coupling with different commercially available boronic acids in the presence of ionic liquids or in conventional solvents. The obtained compounds were tested for their luminescence properties.

The 1,3,4-thiadiazole core has attracted significant attention due to its unique electronic structure, physicochemical properties, and wide-ranging pharmacological potential. This heterocyclic scaffold exhibits a broad spectrum of biological activities, often attributed to its capacity to modulate enzyme function, interact with receptors, and disrupt key biochemical pathways in both pathogens and host cells. Additionally, 1,3,4-thiadiazoles typically display favorable pharmacokinetic properties, including high metabolic stability and appropriate lipophilicity, which enhance their drug-likeness and bioavailability. This review presents an overview of antibacterial and antifungal compounds bearing the 1,3,4-thiadiazole scaffold that have been reported over the past five years. This publication details the chemical structures of novel 1,3,4-thiadiazole derivatives and reports the results of antibacterial and antifungal activity assays conducted against a range of microbial strains. Furthermore, it provides conclusions regarding the structural features that influence the observed biological activity of the synthesized compounds. Antimicrobial activity assessments conducted against ten Gram-negative and nine Gram-positive bacterial strains revealed that 79 newly synthesized 1,3,4-thiadiazole derivatives exhibited either superior inhibitory efficacy relative to standard reference antibiotics or achieved a high level of bacterial growth suppression, defined as 90–100% inhibition. In antifungal assays, the compounds were evaluated against 25 fungal species representing 15 genera. Among the tested derivatives, 75 compounds demonstrated antifungal potency exceeding that of reference antifungal agents or produced growth inhibition within the 90–100% range. The information provided herein may serve as a valuable resource for medicinal and agricultural chemists engaged in the development of novel drug candidates and plant protection agents.