throughput (kg/hr) 250 Max. metering rate (cc/s) 10 Continuous use No Transfer pumps N/A Metering pumps PC/Peri Interchangeable cassette Yes Note: PC = Progressing Cavity Pump Peri = Peristatic Pump PLANETPAK™ CONTAINERS AND LN PACKAGING OPTIONS The FlexCart suite of metering systems is designed to work with the standardized PolyOne range of packaging typically achieving 99% reliable yield on continuous operating systems, while at the same time also achieving a sustainable packaging format in terms of full recyclability.

end life” New designs for energy and carbon efficiency New applications for used and recycled plastics Page 31 Therma-Tech™ LED Lighting • Replaces metal in LED lighting • Extends LED durability and life span eliminating hot spots • Greater design flexibility with • Greater design flexibility with fewer parts • Weight reduction • Simplifies manufacturing and lowers total production cost Page 32 Decreasing Decreasing Dependence on Dependence on Fossil FuelsFossil Fuels Globalizing and Globalizing and LocalizingLocalizing Protecting the Protecting the EnvironmentEnvironment Protecting the Protecting the EnvironmentEnvironment Improving Improving Health and Health and WellnessWellness Improving Improving Health and Health and WellnessWellness Alignment with Megatrends • Aging population • Longer life expectancy • Healthy living • Aging in place • Aging population • Longer life expectancy • Healthy living • Aging in place • Environmental consciousness • Alternative energy • Resource efficiency • Biotechnology • Environmental consciousness • Alternative energy • Resource efficiency • Biotechnology • Global leader/local expert with customized solutions • Global OEMs seeking one standard of service everywhere • Global leader/local expert with customized solutions • Global OEMs seeking one standard of service everywhere • Efficiency focus • Reduced size/weight • Mass transit • Alternative materials • Electric vehicles • Efficiency focus • Reduced size/weight • Mass transit • Alternative materials • Electric vehicles Page 33 48.7% $40.5 26.3% Research & Development Spending Specialty Platform Vitality Index Progression* Innovation Drives Earnings Growth Specialty Platform Gross Margin % * Percentage of Specialty platform revenue from products introduced in last five years 19.5% 2006 2011PF $20.3 2006 2011PF 14.3% 2006 2011PF ($ millions) Page 34 StrategyStrategy PolyOne Innovation Framework Unmet Needs Identification Idea Generation and Shaping Offering Offering Offering Offering Phased Offering Launch Offering Offering LaunchLaunch Offering Offering DevelopmentDevelopment Market Penetration and Value Maximization Intellectual Property ● Resources ● CultureIntellectual Property ● Resources ● Culture Page 35 • Accelerate growth in targeted industries and expand geographic presence through market-driven innovations • Leverage new talent, tools, and training to drive customer satisfaction and margin expansion Critical Imperatives satisfaction and margin expansion • Translate best practices to / from ColorMatrix • Drive specialization using a value-based mindset Page 36 Page 37

It’s in this spirit that we joined legacy PolyOne and the Clariant Masterbatch business, two complementary businesses, and formed a new one that we’ve named Avient. We are better together through: Keeping Safety First — PolyOne and Clariant are both ACC Responsible Care® companies, and nothing is more important than the health, safety and well-being of our people. Leading in Sustainability — PolyOne and Clariant are both founding members of the Alliance to End Plastic Waste, and we are committed to meeting the needs of the present without compromising the ability of future generations to do the same.

It’s in this spirit that we joined legacy PolyOne and the Clariant Color business, two complementary businesses, and formed a new one that we’ve named Avient. We are better together through: Keeping Safety First — PolyOne and Clariant are both ACC Responsible Care® companies, and nothing is more important than the health, safety and well-being of our people. Leading in Sustainability — PolyOne and Clariant are both founding members of the Alliance to End Plastic Waste, and we are committed to meeting the needs of the present without compromising the ability of future generations to do the same.

Avient was formed as PolyOne Corporation on August 31, 2000 from the consolidation of The Geon Company (Geon) and M.A. Wulfsohn 73 AVIENT CORPORATION Exhibit 23.1 CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM We consent to the incorporation by reference in the following Registration Statements: (1) Registration Statement (Form S-8 No. 333-238246) pertaining to the PolyOne Corporation 2020 Equity and Incentive Compensation Plan; (2) Registration Statement (Form S-8 No. 333-231236) pertaining to the PolyOne Supplemental Retirement Benefit Plan (As Amended and Restated Effective January 1, 2014); (3) Registration Statement (Form S-8 No. 333-217879) pertaining to the PolyOne Corporation 2017 Equity and Incentive Compensation Plan; (4) Registration Statement (Form S-8 No. 333-205919) pertaining to the Amended and Restated PolyOne Corporation 2010 Equity and Performance Incentive Plan; (5) Registration Statement (Form S-8 No. 333-181787) pertaining to the PolyOne Corporation 2010 Equity and Performance Incentive Plan; (6) Registration Statement (Form S-8 No. 333-166775) pertaining to the PolyOne Corporation 2010 Equity and Performance Incentive Plan; (7) Registration Statement (Form S-8 No. 333-157486) pertaining to the PolyOne Retirement Savings Plan; (8) Registration Statement (Form S-8 No. 333-47796) pertaining to Post-Effective Amendment No. 3 on Form S-8 to Form S-4 pertaining to the Geon Company 1993 Incentive Stock Plan, the Geon Company 1995 Incentive Stock Plan, the Geon Company 1998 Interim Stock Award Plan, the Geon Company 1999 Incentive Stock Plan, the PolyOne Corporation Deferred Compensation Plan for Non-Employee Directors and the M.A. Hanna Company Long-Term Incentive Plan; (9) Registration Statement (Form S-8 No. 333-141029) pertaining to the PolyOne Retirement Savings Plan and the DH Compounding Company Savings and Retirement Plan and Trust; and (10) Registration Statement (Form S-3 No. 333-236116) of PolyOne Corporation of our reports dated February 22, 2022, with respect to the consolidated financial statements of Avient Corporation and the effectiveness of internal control over financial reporting of Avient Corporation, included in this Annual Report (Form 10-K) of Avient Corporation for the year ended December 31, 2021.