For their wide spectrum applications in biology [ 1 ] 1,2,4-triazoles and 1,3,4-thiadiazoles possess diverse types of biological properties, such as antimicrobial [ 2 ], antibacterial [ 3 ], antitubercular [ 4 ], anti-inflammatory [ 5, 6 ], and antihypertensive [ 7 ] activities, etc. <...> Moreover, triazolothiadiazole can be viewed as a cyclic analogue to two very important components: thiosemicarbazide and biguanide, which often display diverse biological properties. <...> Herein, a new compound of the 1,2,4-triazolo[ 3,4b][1,3,4]thiadiazole ring system is synthesized and its X-ray crystal structure is revealed. <...> The 6-ferrocenyl-3-phenyl-[1,2,4]triazolo[ 3,4-b][1,3,4]thiadiazole compound is synthesized by the previously reported procedure with minor modifications [ 8 ], as shown in Scheme 1. . 944 – 946 Scheme 1. <...> Synthesis of 6-ferrocenyl-3-phenyl-[1,2,4]triazolo[ 3,4-b][1,3,4]thiadiazole A mixture of benzoic acid (1 mmol) and thiocarbohydrazide (1 mmol) was warmed up to 170 C for 1 h. <...> After cooling, water was added into the solution. <...> Then, a mixture of 5-benzoic-4-amino-3-merapto-1,2,4-triazole (1 mmol) and ferrocenecarboxylic acid (1 mmol) in phosphoryl chloride was refluxed for 6 hours. <...> The residue was poured into ice water and the mixture was stirred at room temperature for one hour; sodium bicarbonate was added into the solution gradually until the solution was neutral. <...> The precipitated solid was filtered, dried and recrystallized to get the pure product, which was dissolved in methanol, followed by adding petroleum ether to get the mixed solution. <...> The crystallographic data collections were carried out on a Bruker Smart Apex II CCD area-detector diffractometer with graphite monochromated MoKh radiation (y = 0.71073 Е) at 293(2) K using the -scan technique. <...> The diffraction data were integrated using the SAINT program [ 9 ], which was also used for the intensity corrections for Lorentz and polarization effects. <...> Semiempirical absorption correction was applied using the SADABS program [ 10 ]. <...> The structures were solved by direct methods and all the non-hydrogen atoms were refined anisotropically on F2 by the full-matrix least-squares technique using the SHELXL-97 crystallographic software package [ 11 ]. <...> Selected bond lengths and angles are listed in Table 2. <...> The titled compound <...>