Using bound vars as argument to `to-attr` in macro produces no results. Not sure what mistake I'm making.

core.cljs

(ns my-project.core
  (:require-macros [my-project.macros :refer [style-el]]))

(defn create-el [kind]
  (. js/document (createElement (name kind))))

(let [div (create-el :div)]
  ;; Works as expected
  (style-el div :width "50%")

  ;; Produces no results
  (doseq [[x y] {:width "25%" :color "#fff"}]
    (style-el div x y)))

macros.clj

(ns my-project.macros)

(defn to-attr [attr]
  (symbol (str ".-" (name attr))))

(defmacro style-el [el kwd value]
  `(set! (-> ~el .-style ~@(to-attr kwd)) ~value))

Yes the problem here is that you're trying to have runtime code interact with macro code which really isn't possible. style-el is probably just best written as a plain function.