A series of new benzimidazole phosphonate derivatives was obtained via nucleophilic addition of triethyl phosphite to the imine of the imidazole subgroup under solvent-free conditions. Structures of the formed products were confirmed using spectroscopic data (ATR-FTIR, ¹H-NMR, ¹³C-NMR, and MS). The antimicrobial profiles of the synthesized compounds were examined, and promising activities against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans were revealed, showing significant inhibition zone diameters ranging from 13 to 17 mm. Alongside these experimental findings, in silico investigations were conducted using ADMET characteristics, which showed a positive pharmacokinetic profile and provided valuable information on potential interactions with target molecules. Besides, docking studies against tested microorganisms revealed further insights on the compounds’ binding interactions with the active sites. Finally, DFT analysis was performed to shed light on the synthesis of novel molecules.