Herein we report a sustainable and efficient synthesis of a few chosen five- and six-membered fused nitrogen heterocycles such as benzimidazole, and quinazolinone catalyzed by immobilization Ni NPs on pyridine-functionalized multi-walled carbon nanotubes (MWCNTs). This novel heterogeneous nanostructure catalyzed acceptorless dehydrogenative coupling of alcohols with 1,2-phenylenediamine and condensation of alcohols with 2-aminobenzamide, respectively in the synthesis of 2-substituted benzimidazoles and 2-substituted quinazolinones, with high activity, selectivity, and reusability. Furthermore, the resultant heterogeneous nanocatalyst showed the efficient catalytic synthesis of 1,2-disubstituted benzimidazoles from a hydrogen borrowing approach, involving low-cost alcohols as hydrogen donors and o-nitroaniline as hydrogen acceptors. To further study, the theoretical inhibitory activity of the newly synthesized compounds against α-glucosidase was studied by molecular docking. In silico results showed that among all the studied compounds, the 8d and 8g derivatives are the best candidates as effective inhibitors of α-glucosidase.