Isis Draw was a popular, lightweight chemical structure drawing program used in the late 1990s and 2000s. Version 2.4 was one of its last stable free releases.
MDL/Accelrys stopped supporting Isis Draw nearly two decades ago. The “free download” you find is not hosted by the original company. It’s been passed around forums, file-sharing sites, and old university servers. Isis Draw 2.4 Free Download
Use an open-source converter like OpenBabel (free, command-line based) to translate the file into a modern format, then open it in one of the tools above. Isis Draw was a popular, lightweight chemical structure
The software served its purpose admirably in the early 2000s, but chemistry software has evolved. The modern free tools listed above are safer, more powerful, and actually supported. The “free download” you find is not hosted
This is the most important point. Software that hasn’t been updated since the Windows XP era was not built for modern security threats. Downloading an old .exe from an unknown source is a leading cause of malware, ransomware, and keyloggers. You have no way of knowing if the file has been modified to include a virus.
Stay safe, and draw your molecules responsibly. Have a memory of using Isis Draw back in the day? Or a question about migrating old chemical files? Drop a comment below.