Owned by Evanov Communications, the station broadcasts a rhythmic contemporary format targeting the Greater Toronto Area.

[1] Due to its signal location near Orangeville, the station covers Barrie and Kitchener in addition to rimshotting Downtown Toronto.

On September 28, 1994, the CRTC approved the ownership transfer of Dufferin Communications from its shareholders to CKMW Radio Ltd., operator of Brampton multicultural station CIAO.

In late December 2000, the station was re-branded as Z103.5 (with the decimal point heard as "dot"), with the slogan "The Hit Music Channel", though the CIDC call letters were retained.

Until the summer of 2006, CIDC was the only radio station in Canada that played dance music since CING-FM changed formats in 2001.

However, while the Winnipeg station continues to do well, the Halifax outlet would see their fortunes take a downturn in ratings and format changes that resulted in their flip to Country in September 2015.

At that same time, CIDC did the reverse: from mainstream to a rhythmic-lean, although it still plays a small percentage of dance music, which was slightly increased by 2015.

Recently, as of 2008, high-profile guest DJ's have started to mix live for the Drive @ 5 on several occasions including David Guetta, Tiesto, and Armin van Buuren (his show A State of Trance can be heard Sunday nights on this station).

Evanov stated that the move would help to improve reception in Downtown Toronto (especially inside buildings) to add one million potential new listeners, and deploy HD Radio services simulcasting CIAO and CIRR-FM.

The application was denied by the CRTC, citing that the proposed changes would reduce coverage in Orangeville and increase its strength in an out-of-market area, thus neglecting its city of licence.

As a condition of its licence renewal, the CRTC ordered the station to regularly broadcast content of direct and particular relevance to Orangeville (including news headlines and other local information), traffic and weather reports for markets within its signal contours, refrain from exclusively devoting this coverage to Toronto, and to identify as an Orangeville station.

The application was denied by the CRTC on January 31, 2020, who ruled that it would undermine the commission's competitive licensing process, and cited technical restrictions related to use of the frequencies in both markets.

Its sister station in Halifax also started holding a similar Summer Rush concert in 2007, usually around the same time as its Toronto sibling.

The Summer Rush has been held at various venues over the years, including the Molson Amphitheatre at Ontario Place, Polson Pier (previously known as The Docks), and, more recently, the Kingswood Theatre at Canada's Wonderland.

There have been over a hundred artists featured from Europe, South America, USA, and Canada, including Real McCoy (twice – 1997 and 2009), Culture Beat (twice – 1993 and 2004) Cascada (three times – 2004, 2006, 2008), DHT, B4-4 (a crowd favourite), Joee, Sarina Paris, Len, The Boomtang Boys, Snap!, Waldo's People, Do (singing DJ Sammy's "Heaven"), Haiducci, DC Project, Jam & Spoon, Elissa, Stevie B, Ian Van Dahl, Sash!, Rupee, Kevin Lyttle, Jesse McCartney, JoJo, Elise Estrada, Basshunter and Daddy Yankee.

[8] On March 23, 2016, Wayback Wednesdays returned to Z103.5, back by popular demand, broadcasting live from Ristorante Buonanotte.