A series of novel [1,2,4]triazolo[4′,3′:1,5][1,2,4]triazolo[3,4‐b][1,3,4]thiadiazines (4a‐p) were synthesized from the reaction of 4‐amino‐5‐hydrazinyl‐4H‐1,2,4‐triazole‐3‐thiol (1) with different bromoethanones (2a‐p) and substituted benzoic acids (3) via a one‐pot, three‐component reaction with good to excellent yields. The new fused tri‐cyclic system was achieved without using a catalyst and metal by cyclo‐condensation reaction through a one‐pot approach. The structures of newly synthesized molecules were confirmed by using IR, 1H‐NMR, 13C‐NMR, Mass spectral, and analytical data. Molecular docking studies were carried out for the newly synthesized compounds against human cancer receptors (2TKB) with good results.