CasualPConc 0.8.2 for Mac was available as a free download on our application library. The application is included in Productivity Tools. The actual developer of this free software for Mac is Yasu Imao.
From the developer:
CasualPConc is a simple parallel concordancer for 2 parallel corpora. To use CasualPConc, you need corpus files that are aligned. The supported file formats are Plain Text (.txt), Rich Text (.rtf), MS Word (.doc/.docx), and OpenOffice (.odt/sxw). But to be safe, Plain Text files (.txt) are recommended. For Plain Text files, various text encodings are supported, but UTF-8 is the default and recommended.
You may want to check out more Mac applications, such as Combine PDF's, ShinyDroplets2 or MakeDocJ, which might be related to CasualPConc.