Acid-base bifunctioanal ionic liquid, 1-(2-(1'-piperidinyl) ethyl)-3-methyl imidazolium trichlorolead ([PEmim]PbCl(3)), is an efficient catalyst for the reaction of aniline and dimethyl carbonate (DMC). The [PEmim]PbCl(3) catalyzed reaction gives methyl-N-methyl-N-phenylcarbamate in the yield of 72%, while the basic ionic liquid, 1-(2-(1'-piperidinyl) ethyl)-3-methyl imidazolium chloride, and the acidic PbCl(2) give the yields of 47% and 6%, respectively. The high reactivity of [PEmim]PbCl(3) is accounted for its ability to activate both aniline and DMC by the acidic and basic sites cooperatively. Density functional theory (DFT) calculations simulate the structures and charge properties of [PEmim]PbCl(3), complex of [PEmim]PbCl(3) and aniline, and complex of [PEmim]PbCl(3) and DMC. The calculations show that [PEmim]PbCl(3) can increase the electrophilicity of DMC and the nucleophilicity of aniline by its acid and base sites. (C) 2010 Elsevier B.V. All rights reserved.