The Times today reports that the talks were between the groups' chief executives Ralph Bernard and Tom Moloney, and broke down when Moloney resigned from Emap last month.
However, GCap is still said to be keen to unite the UK's top two commercial radio groups.
The paper claimed Bernard "might be prepared" to stand down in order to effect the merger, which would bring together strong brands such as GCap's Capital and Classic FM and Emap's Magic.
The Times says it was told by Bernard in April that the merger would be in the clear with regulator Ofcom, judging by Ofcom's analysis in its The Future of Radio report.
However, a deal would also require clearance from the Competition Commission.
Talks did not reach the stage of deciding on a ownership structure.
Whether the companies return to discussions depends on who emerges at the head of Emap. Alun Cathcart, Emap chairman, has taken temporary charge while the company searches for a new chief executive.