Computational chemistry researchers have many tools at their disposal. Investigations of reactions with smaller molecules of fewer than 200 atoms can be automated using tools such as AaronTools using AARON. Pd-catalyzed arylboronic acid additions with the novel pyridine-dihydroisoquinoline (PyDHIQ) ligand have been studied with AARON and AaronTools to determine origins of selectivity and reinvestigate the previously established mechanism. Systems larger than those typical of organometallic catalysis systems cannot be studied using AaronTools. ONIOM in Gaussian uses hybrid methods which can be used to investigate large systems by treating a small portion of a system with more costly methods and the whole system with less costly methods. Previously developed tools for automating ONIOM computations are insufficient in accomplishing the necessary tasks for ONIOM job preparation. AarOniomTools is a collection of additional functions to AaronTools that accelerates the preparation of ONIOM computations with file handling, automatic solvent detection, and automatic layer partitioning capabilities.