Cassidy Michalski, 24, of Deerfield and Nicholas Taverna, 22, of Greenfield were arrested for unarmed robbery, assault and shoplifting, The (Springfield) Republican reported.
Court documents said the two men told police they went to a Walmart in Northampton intending to steal cellphones they could sell to buy heroin.
While in the store, Taverna spotted some Girl Scouts sitting behind a table selling cookies.
Police said he pretended he wanted to buy some cookies and snatched the metal box containing the cookie money.
A male troop leader followed Taverna out to the getaway car and pounded on the vehicle.
The leader suffered a broken nose when he was thrown to the ground as the defendants sped away.
A pretrial hearing for the two is set for Feb. 22.