Hello Leslie, happy to help.

Since there is so much lilac leaf blight going around in the metro area, I'm assuming that is the problem with your shrubs. I've included the best advice about lilac leaf blight, written by a fellow AskExtension expert, Steve Miles.

We've had a very wet spring and early summer and this is usually the result. Your lilacs may look awful but they're not dead and they'll likely look great next year provided you clean up all the leaf debris underneath them before winter so that the disease cause is not splashed back up into the shrubs during next year's spring rains. Here is Steve's information:

Many of you are experiencing lilac blight where the leaves of your lilacs are going brown, almost as if they are charred. My lilacs have this condition as well.
This is a combination of my advice, advice from various University websites and from Hort Professor Emeritus Dr. Stephen Hedman

Lilac blight is extremely common in the Metro area. Some comments:
1). It could be caused by a bacterium Pseudomonas syringae which has leaf
darkening, leaf wilting, and leaf dropping. This is largely a cosmetic
condition and unless it occurs for several years has no adverse effects.
It is associated with wet conditions, as during this summer. This
is NOT a fungus; fungicides are of no use. It can be transmitted
from one season to the next via leaf debris. Thus, to prevent
transmission thorough fall cleanup is essential. See here for information https://extension.umn.edu/plant-diseases/leaf-spot-diseases-trees-and-shrubs#bacterial-leaf-spots-and-blight-1156513andhttps://yardandgarden.extension.iastate.edu/encyclopedia/lilac-bacterial-blight#:~:text=Symptoms%20of%20lilac%20bacterial%20blight,Eventually%2C%20leaves%20may%20be%20killed.
and https://extension.oregonstate.edu/news/how-recognize-treat-avoid-lilac-bacterial-blight

2). It could be caused by Cercospora or Septoria fungi. The symptoms are
small, brown to black spots appearing on lilac leaves that are
surrounded by a yellow halo. The leaves will become distorted and drop
prematurely.
See: https://extension.missouri.edu/media/wysiwyg/Extensiondata/Pro/PlantDiagnosticClini
c/Docs/leaf-spot-on-lilac.pdfandhttps://yardandgarden.extension.iastate.edu/article/2021/08/summer-foliar-lilac-diseases

3). It is not important which type of blight it is; it should not kill your
lilacs. Do not feel that they must be dug up immediately and
discarded. They will recover although their blooming may be delayed by a
season or two.
If you must know what disease you have, you can send a sample to: https://pdc.umn.edu/

Good-luck!