Our website provides a free download of PLT 7.1.17. The program's installer files are generally known as PLT Database Start.exe or PLT71.exe etc. PLT lies within Education Tools, more precisely Science Tools. The most popular version among the software users is 7.1. This free software is an intellectual property of Hans J. Reich.
From the developer:
PLT is a program for producing chemical drawings and outputting them in a variety of formats.
PLT provides routines for producing all rings and line types used in chemical structures, formatted text material in any TrueType font installed on your system (including greek characters and special chemical characters like radical anion, radical cation, double dagger) and supports the use of color.
You may want to check out more software, such as PLT Scheme, PLTS for ArcGIS - Foundation or wxMacMolPlt, which might be related to PLT.