Reductive alkylation and reductive methylation of aromatic primary amines with carbonyls and 37% formaldehyde using decaborane in one-pot way gave the corresponding tertiary amines in high yields. The reaction condition was extended for the reduction of nitroaromatic using decaborane and Pd/C followed by the reductive alkylation and reductive methylation using decaborane to give the corresponding tertiary amines in high yields.