Congressional Quarterly Inc., whose Weekly Report magazine on Congress, politics and national issues is a staple of the Washington reading diet, has expanded its empire with the purchase of five publications from The Washington Monitor Inc.

The five publications are The Congressional Monitor, a daily report on congressional committee activities; The Weekly Congressional Monitor; The Congressional Record Scanner; Congress in Print, and Congress Daily.

In announching the purchase agreement, CQ president and editor Eugene C. Patterson said CQ would take over publication of the periodicals Aug. 1.

The Congressional Monitor has a daily circulation of more than 1,000, mostly to lawyers, lobbyists, bankers, government officials and corporate executives. "We believe the daily Monitor and related publications are essential references for people who need to stay ahead of what is coming up in Congress or cut through the information on what has happened," said CQ publisher Wayne Kelley.

The Washington Monitor will continue to publish independently the Congressional Yellow Book and the Federal Yellow Book, two loose-leaf directories, and The Weekly Regulatory Monitor and the Access Reports/Freedon of Information, two newsletters.

CQ Inc., a wholly owned subsidiary of the St. Petersburg Times Publishing Co., also publishes hard-bound rreference books, college textbooks, paperback books on public affairs and Congressional Insight and Campaign Practices Reports, two newsletters.

The Washington Monitor, founded in 1965, was acquired in 1969 by "Up the Organization" author Robert C. Townsend and New York investment banker Donald A. Petrie.