diff --git a/EXAMPLES.md b/EXAMPLES.md
index d4c6dda..399965e 100644
--- a/EXAMPLES.md
+++ b/EXAMPLES.md
@@ -219,7 +219,7 @@ Aligning in-line comments
 -------------------------
 
 *Note: Since the current version provides '#'-rule as one of the default rules,
-you can ignore this section*
+you can ignore this section.*
 
 ```ruby
 apple = 1 # comment not aligned
diff --git a/README.md b/README.md
index fc90674..33ed24a 100644
--- a/README.md
+++ b/README.md
@@ -90,7 +90,7 @@ shortcuts for the most common use cases with the concept of "_alignment rule_".
 
 An *alignment rule* is a predefined set of options for common alignment tasks,
 which is identified by a single character, *DELIMITER KEY*, such as `<Space>`,
-`=`, `:`, `.`, `|`, `&`, and `,`.
+`=`, `:`, `.`, `|`, `&`, `#`, and `,`.
 
 Think of it as a shortcut. Instead of writing regular expression and setting
 several options, you can just type in a single character.
@@ -149,7 +149,7 @@ With these mappings, you can align text with only a few keystrokes.
     - `-`         Around the last occurrences of delimiters (`-1`)
     - `-2`        Around the second to last occurrences of delimiters
     - ...
-1. Delimiter key (a single keystroke; `<Space>`, `=`, `:`, `.`, `|`, `&`, `,`)
+1. Delimiter key (a single keystroke; `<Space>`, `=`, `:`, `.`, `|`, `&`, `#`, `,`)
 
 #### Predefined alignment rules
 
@@ -452,7 +452,9 @@ For example if you set `ignore_groups` option to be an empty list, you get
 }
 ```
 
-Satisfied? :satisfied:
+If a pattern in `ignore_groups` is prepended by a `!`, it will have the opposite
+meaning. For instance, if `ignore_groups` is given as `['!Comment']`, delimiters
+that are *not* highlighted as Comment will be ignored during the alignment.
 
 ### Ignoring unmatched lines
 
@@ -674,7 +676,7 @@ let g:easy_align_delimiters = {
 \ '/': {
 \     'pattern':         '//\+\|/\*\|\*/',
 \     'delimiter_align': 'l',
-\     'ignore_groups':   ['^\(.\(Comment\)\@!\)*$'] },
+\     'ignore_groups':   ['!Comment'] },
 \ ']': {
 \     'pattern':       '[[\]]',
 \     'left_margin':   0,
diff --git a/autoload/easy_align.vim b/autoload/easy_align.vim
index c5a061f..4de8956 100644
--- a/autoload/easy_align.vim
+++ b/autoload/easy_align.vim
@@ -37,8 +37,7 @@ let s:easy_align_delimiters_default = {
 \  ',': { 'pattern': ',',  'left_margin': 0, 'right_margin': 1, 'stick_to_left': 1 },
 \  '|': { 'pattern': '|',  'left_margin': 1, 'right_margin': 1, 'stick_to_left': 0 },
 \  '.': { 'pattern': '\.', 'left_margin': 0, 'right_margin': 0, 'stick_to_left': 0 },
-\  '#': { 'pattern': '#\+',
-\              'delimiter_align': 'l', 'ignore_groups': ['^\(.\(Comment\)\@!\)*$'] },
+\  '#': { 'pattern': '#\+', 'delimiter_align': 'l', 'ignore_groups': ['!Comment']  },
 \  '&': { 'pattern': '\\\@<!&\|\\\\',
 \                          'left_margin': 1, 'right_margin': 1, 'stick_to_left': 0 },
 \  '{': { 'pattern': '(\@<!{',
@@ -91,7 +90,11 @@ function! s:highlighted_as(line, col, groups)
   if empty(a:groups) | return 0 | endif
   let hl = synIDattr(synID(a:line, a:col, 0), 'name')
   for grp in a:groups
-    if hl =~# grp
+    if grp[0] == '!'
+      if hl !~# grp[1:-1]
+        return 1
+      endif
+    elseif hl =~# grp
       return 1
     endif
   endfor