Diagram that should appeal to Desperate Dan! (3,5)
I believe the answer is:
pie chart
'diagram that should appeal to desperate dan' is the definition.
'pie chart' can be an answer for 'diagram'. I am not certain of the remainder of the definition.
'diagram' is the wordplay.
I cannot quite understand how this works, but
'diagram' could be 'chart' (I've seen this before) and 'chart' is located in the answer.
The remaining letters 'pie' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
(Other definitions for pie chart that I've seen before include "Display of data r" , "Circle divided by radii to depict percentages of the whole" , "Illustration of shares" , "Display of information" , "Graph of a circle divided into sectors" .)