Sodium bisulfite has been reported first time for the synthesis of 2,5-disubstituted 1,3,4-oxadiazole using microwave and conventional method in ethanol-water. The yields obtained are in the range of 90-95% using microwave and 87-91% using conventional method. All the synthesized compounds (8a-8s) are novel and were evaluated for their in vitro antifungal activity. SAR for the series has been developed by comparing their MIC values with miconazole and fluconazole. Some of the compounds from the series like 8k was equipotent with miconazole against Candida albicans and Fusarium oxysporum. Also compound 8n was equipotent with miconazole against F. oxysporum.