Devonthink (Pro) supports rich text format writing. But I prefer emacs orgmode format to rich text format. This elisp code is for exporting orgmode document into Devonthink document.

(defun org-export-to-devonthink (arg)
  "Call `org-export-to-devonthink` with output to a temporary buffer.
   No file is created."
  (interactive "P")
  (let (content)
    (org-export-as-html arg nil nil "*Org HTML Export*")
    (switch-to-buffer "*Org HTML Export*")
    (setq content (buffer-string))
    (kill-buffer "*Org HTML Export*")
    (setq content (replace-regexp-in-string (regexp-quote """) """ content t t))
    (do-applescript
     (format "tell application id "com.devon-technologies.thinkpro2"
create record with {name:get title of "%s", 
type:html, source:"%s", url:"%s"} in current group
end tell
" content content (buffer-file-name)))
    )
  )
(global-set-key [f8] 'org-export-to-devonthink)

I bind org-export-to-devonthink to [F8] key. After writing the document, press [F8]. This script exports the orgmode article in the format of HTML and save it to the selected group in Devonthink Pro.

By Launch URL command in Devonthink Pro, you can jump to original orgmode article.

Original orgmode article

Exported HTML article saved in Devonthink Pro