Formating data series based on specific text

Most strategies for "conditional formatting" of chart data are some variation on "use a different series for each color/format that you want": https://peltiertech.com/conditional-...-excel-charts/

So, in your case, I would add a formula to column C that says "If august then N/A else value" [=IF($A2="ago",NA(),$B2)] and an inverse formula in column D that says "If august then value else N/A" [=IF($A2="ago",$B2,NA())]. Then maybe use a stacked column rather than a clustered column. Format the column C data series to be blue, and the column D data series to be yellow.

Thanks, that sounds like a long workaround though.
The biggest problem to this approach is that I must use different types of charts and would involve changing a lot of the architecture of existing sheets.

Plus I have cases where I need to have more that 1 name series marked in diff colours

Nothing possible on the charts directly?

I don't know what consititutes a "long" workaround in your opinion, but this approach is usually considered the easiest to build and maintain. There are no built in options in Excel's chart engine, so you can't just tell the chart to format certain points differently. I also cannot see how much work this would really require to modifying the architecture of existing sheets (I would note that rather than modifying existing architecture, I would probably add a helper range to build the chart data series in an out of the way or even hidden block of cells).

You can format individual points in a data series in the chart. For a year that begins in Jan and ends in Dec, you could format the 8th data point to be yellow while the rest of the data series is blue. If August will always be the 8th data point, then this can work, but your OP suggests that August will not always be the 8th point, and your latest post suggests that you may have cases where you format other months as yellow. The trouble with formatting individual data points is that, each time you need to change which point is yellow, you need to format the entire data series back to its "blue" color, then identify which points need to be yellow and format those data points individually as yellow.

You can write a VBA macro to try to automate that process. I don't know what your experience is with VBA, but this is usually considered more difficult. If you are interested, this tutorial (linked to in the previous tutorial) walks you through the VBA of such a procedure. https://peltiertech.com/vba-conditio...arts-by-value/