To highlight the importance of thiazole and thiadiazole derivatives in the progression of cancer and microbial treatments and to aid in drug design, we have synthesized a new series of 1,3,4-thiadiazole and 1,3-thiazole derivatives. These were created by a two-step reaction process: initially, 2-(4-(2-bromoacetyl)phenyl)isoindoline-1,3-dione was reacted with potassium thiocyanate, and then the resulting thiocyanate intermediate was coupled with aryl diazonium salts to produce iminothiadiazole derivatives. These derivatives served as crucial intermediates for further synthesizing a range of thiadiazole derivatives using different reagents. Additionally, treating 2-(4-(2-bromoacetyl) phenyl)isoindoline-1,3-dione with thiourea resulted in aminothiazole derivatives. These were further coupled with arenediazonium chloride to form 5-arylazoaminothiazole derivatives. All the synthesised compounds were characterised using IR, 1H NMR and 13C NMR spectrum data, as well as physical data. The assessment of the synthesized compounds on the HCT-116 human colon cancer cell line has yielded promising results. Specifically, compounds 3a, 3b, 4b, 5b, 6b, and 9b have shown noteworthy efficacy, suggesting their potential as anticancer agents. These compounds have demonstrated a greater potency compared to the standard drug, doxorubicin, highlighting their significance in cancer treatment research. The study assessed the activity of various newly synthesized compounds against diverse microorganisms, including bacteria and fungi. Notably, two of these compounds, specifically 4b and 7b, exhibited significant efficacy against both gram-positive and gram-negative bacteria, surpassing the performance of a standard antibacterial reference agent. Furthermore, molecular docking of new products revealed interactions with enzyme binding sites, aligning with in vitro findings. Additionally, in-silico studies confirmed their favourable oral bioavailability through ADME profiling.