An efficient and convenient approach towards the synthesis of nitrogen fused imidazoheterocycles through double C-N bond formation in a single step has been achieved with a good range of substituted phenacyl bromides in the presence of magnetically recoverable Fe3O4 as a green heterogeneous nanocatalyst. The present approach was found to be environmentally benign and economically feasible in view of its ease of application, low cost and easy separation. Developed methodology has several advantages such as wide scope of substrates, easily available catalyst, operationally simple and high yield. Moreover, the magnetically separable catalyst was easily separated from the reaction mixture using an external magnet and recycled up to four times without much lost in its catalytic activity. Manuscript profile