The novel class of multi-substituted indolylimidazole derivatives series substituted 3-(4,5-diphenyl-1H-imidazol-2-yl)-1H-indole and substituted 5-bromo-3-(4,5-diphenyl-1H-imidazol-2-yl)-1H-indole was synthesized utilising a green and efficient one-pot four components condensation of indole-3-carbaldehyde, benzil, ammonium acetate and various amines under microwave irradiation using Amberlyst A-15 as a recyclable catalyst. The catalyst Amberlyst A-15 has recovered from the reaction mixture and reused repeatedly for the next reaction. The key advantage of this process involves eco-friendly, very short reaction time, cost-effectiveness with the reusability of catalyst, easy workup, and purification of the product with excellent yields. FTIR, 1HNMR and Mass spectrometric studies analyzed and established the structures of all newly synthesized compounds.

Indolylimidazole compounds that contain both indole and imidazole rings have shown various biological and pharmacological activities. These indolylimidazole compounds have been synthesized and extracted from the plants. In this paper, we have reviewed biological activities of natural and synthesized indolylimidazoles and their various synthetic methods. In recent time, the substituted indolylimidazole derivatives have synthesized and reported in the presence of different kind of the catalysts such as strong protic acid HNO₃@nano SiO₂, Zn²⁺@KSF and acetic acid and Amberlyst A-15. This review paper is divided into two categories bases on bioactivities of natural and synthesized indolylimidazole derivatives.