InChISMILES

InChISMILES is a term used in cheminformatics to describe the relationship or workflow that connects InChI strings with SMILES representations of chemical structures. InChI, the IUPAC International Chemical Identifier, is a non-proprietary, layered encoding designed to uniquely identify chemical substances. SMILES, or Simplified Molecular Input Line Entry Specification, is a line notation for encoding chemical structures in a compact textual form. The concept of InChISMILES encompasses processes that convert between InChI and SMILES or that integrate both representations within data workflows.

The main goal of InChISMILES is to enable interoperability between databases and software that prefer either InChI or SMILES. InChI provides a robust, unambiguous descriptor of molecular constitution and stereochemistry, while SMILES is often preferred for human readability and for input into many computational tools. Tools and toolkits such as Open Babel and RDKit implement conversions between InChI and SMILES, allowing researchers to translate identifiers to usable structure strings within pipelines.

Representation and limitations: InChI is designed to be unambiguous, whereas SMILES can be non-unique unless a specific canonicalization method is used. As a result, the InChI-to-SMILES mapping depends on the chosen SMILES generation algorithm, and different implementations may yield different canonical SMILES for the same InChI. This non-uniqueness is a practical consideration in InChISMILES workflows.

Applications and relevance: InChISMILES workflows support database indexing, deduplication, cross-referencing across repositories, and integration of data from sources that store either InChI or SMILES. They are also useful in literature mining and property prediction pipelines that require multiple structural representations. See also InChI, SMILES, InChIKey, and related software toolkits.