Brainstorming, as a pre-writing activity, facilitates the process of generating ideas and helps organize learners' thoughts to get involved in writing activities. The present convergent mixed methods study investigated whether the integration of technology and brainstorming could affect the argumentative writing of EFL learners. Initially, 68 university students in three intact classes (n=26, n=23, n=20) were exposed to mobile-assisted brainstorming (n=26), wordle-assisted brainstorming (n=23), and cooperative brainstorming (n=20) in the quantitative phase. For qualitative data collection, each session, some paper strips with three questions on them were distributed among the groups to help the researchers discover the participants' learning processes and perceptions during the instruction. Sixty-five participants who had attended all treatment sessions took one immediate post-test on a seen and one delayed post-test on an unseen topic. Two one-way analysis of variance tests (ANOVA) examined whether there were statistically significant differences between the means of the groups. The results revealed that the wordle-assisted brainstorming group outperformed the two other groups in both post-tests. The findings supported the use of word clouds as a cognitive activity in promoting the argumentative essay writing of Iranian EFL learners. The study has implications for teachers, practitioners, and educators.