Although we initially followed our previously developed solid-state dehydration protocol for synthesizing 3-X-R, we were motivated by inconsistent yields and long reaction times to investigate a solution-phase method. Unexpectedly, simply heating the tetraacids 2-X with primary amines in acetic acid solvent followed, if necessary, by the precipitation of products with the addition of water or MeOH to the reaction mixture, provided MDIs 3-X-R in up to 93% isolated yield. In some cases, a small amount of additional product can be recovered by extraction of the aqueous filtrate with CH2Cl2. Although the reaction byproducts are often polar and soluble enough in AcOH to be removed during the filtration process, additional purification can be easily achieved by passing the crude product mixture through a SiO2 column. This method is successful with a variety of amines and there is no discernible trend between the identity of the halogen and the reaction yield. Hexylamine, aniline, and benzylamine react smoothly with 2-X (X = Cl, Br, and I) in good yields to produce a suite of 3-X-R compounds. Single crystal X-ray data for 3-Br-Ph confirms the MDI constitution of the products (Figure ). It is notable, as will be discussed below, that yields tend to be higher for the halogenated 3-X-R compounds than the nonhalogenated ones. Amino acid methyl esters can also be readily converted into MDIs, which suggests they may be interesting building blocks for self-assembling small molecules. Attempts to perform imidization with 6-amino-1-hexanol, however, resulted in complex mixtures as a consequence of acetate ester formation with the free alcohol. With these results in hand, we attempted to install more sterically demanding Ngroups such as branched alkyl chains and 2,6-dialkylaryl groups since these are commonly used by organic materials chemists to manipulate crystal packing and solubility. Although 2ethylhexylamine reacted readily with 2-H to yield 3-H-EtHex, imidization of 2-H with the more sterically hindered nucleophiles such as (S)-1-phenylethan-1-amine and 2,6-diisopropylaniline proved to be more recalcitrant. We were unable to isolate any products after applying our standard reaction method, and heating (S)-1-phenylethan-1-amine with 2-H for 3 days at 110 °C resulted in only 11% formation of 3-H-1PhEt. These low yields for sterically hindered amines were also found when attempting these same reactions using our older solid-state approach (Figure ).