Screening Libraries: Key Facts

Small molecule screening libraries for drug discovery and chemical biology

High Quality, Small Molecule Screening Libraries

ChemBridge has been a provider of high quality screening compounds and libraries for hit identification for almost three decades and continues to produce novel, lead-like and drug-like small molecule screening compounds based on the evolving requirements of drug discovery and chemical biology researchers in industry and academia. We currently offer more than 1.3 million small molecule screening compounds that are readily available from stock. Our stock is composed of two complementary parts with no overlap. See the sections later on this page for more details:

Researchers can custom select compounds based on their own requirements or ChemBridge can assist with compound selection. Compounds can be delivered in mg or micromole amounts in a wide range of formats, and plating in customer-specified materials is available. For researchers interested in chemical diversity for use across a range of targets or for exploring novel targets, ChemBridge also offers pre-selected diversity libraries that offer a lower cost per compound compared to custom selections. We also offer a number of targeted and focused sets representing compounds selected from our stock using computational and informatics methods.

Our stock can be searched online by ID or structure at ChemBridge’s Search and Order site. Researchers can also download SDfiles for our stock, our diversity libraries, and our targeted and focused sets. When considering a larger compound acquisition (1,000 or more compounds), we recommend you email ChemBridge Sales to obtain custom SDfile versions to ensure the highest availability at your preferred amount per compound. When virtual screening and planning a smaller compound selection, the standard SDfiles on the download page can be used.

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to view a the PDF summary of our stock.

CORE Library Stock

Our in-house designed CORE Library Stock of sp3-enriched, lead-like, small molecule screening compounds (8-digit IDs) offers more than 800,000 compounds. These high quality compounds are synthesized internally and are based on 1,000 novel, proprietary, synthetic schemes. To maximize diversity, our template and final compound designs draw from ChemBridge’s internal Building Block Collection, from external sources, and from new reagents designed by ChemBridge. New compounds based on novel designs are added each year.

These compounds are designed to cover unique chemical space not available from our EXPRESS-Pick™ Stock and not available from other commercial libraries. Final compound designs are assessed virtually prior to synthesis and only compounds with the most attractive physiochemical property profile and free of undesirable chemical functionalities are synthesized and added to the CORE Library Stock. Because of the lead-like properties of these compounds, more than half of all CORE Library Stock compounds have high CNS MPO scores, making them suitable for CNS focused research and are included in our CNS-MPO Library.

Physiochemical property averages are:

  • Average Molecular Weight: 344
  • Average H-bond Donor Count: 1.1
  • Average H-bond Acceptor Count: 4.1
  • Average clogP: 1.6
  • Average TPSA : 68.7
  • Avegare Rotatable Bond Count: 4.9
  • Average Fsp3: 0.465

EXPRESS-Pick Stock

The EXPRESS-Pick Stock (7-digit IDs) contains over 500,000 small molecule screening compounds. Compounds were selected using novelty, diversity, drug-like property, and chemical structure analyses. Because chemical space covered by the EXPRESS-Pick Stock is different than the chemical space covered by the CORE Library Stock, the EXPRESS-Pick Stock provides access to additional chemotypes for hit finding. Both drug-like and lead-like compounds are represented in the EXPRESS-Pick Stock.

Physiochemical property averages are:

  • Average Molecular Weight: 355
  • Average H-bond Donor Count: 1.1
  • Average H-bond Acceptor Count: 3.8
  • Average clogP: 3.6
  • Average TPSA : 66.8
  • Avegare Rotatable Bond Count: 3.8

Successful Track Record


Almost three decades of excellence as a small molecule library provider and chemistry service provider/partner, including major, multi-year alliances with top pharmaceutical companies.


Over 30 million samples provided to customers worldwide, including all major pharmaceutical and biotechnology companies as well as major academic and non-profit research organizations.

Successful HTS Campaigns

More than 2800 scientific articles that cite ChemBridge libraries or compounds have been published in scientific journals including Science, Nature Cell Biology, JACS, PNAS, JBC, Cancer Research, and many others.

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