This project addressed issues of resolution and discriminatory capabilities in controlled substance analysis with the goal of providing additional reliability and selectivity for forensic evidence and analytical data of piperazines. A number of piperazine-containing compounds have appeared on the illicit drug market in recent years (benzyl-, phenyl-, benzoyl- and designer phenethyl- piperazines) and these compounds may represent a new class of designer drugs. Some of these piperazine compounds are commercially available and others are designer analogues that can be synthesized in clandestine labs. Restricting the availability of piperazine would require placing dozens of substances from commercial sources around the globe under Federal control and modern forensics must be able to identify the compounds, and its analogues, as a controlled substance. Overall, this project evaluated the potential forensic interests of organic synthesis piperazine and more than 100 substitutes. Chemical characterization analysis included common to forensic science lab tools, such as MS and IR. The project has completed the following: 1) Synthesis of aromatic ring substituted benzylpiperazines focusing on those aromatic ring substituents commonly found in ring substituted phenethylamines drugs of abuse and the most significant substituents of isobaric equivalence. 2) Synthesis of aromatic ring substituted phenylpiperazines following the same general protocol. 3) Synthesis of substituted benzoyl-piperazines focusing on aromatic ring substituents of designer interest. 4) Synthesis of selected phenethyl-piperazines. 5) GC-MS evaluation of the regioisomeric and isobaric piperazines. 6) Evaluation of GC methods for the separation of all isomers producing equivalent mass spectra. 7) Evaluation of chemical derivatives of these isomers for differential mass spectral properties. And, 8) Evaluation of GC-MS and IR data for specific differentiation of all isomers producing equivalent mass spectra. 28 Chapters with conclusions and references, Tables and Figures, Appendices.