No it wasn't. The following is the "direct lift" from the Conservapedia. (Nowhere does it say he was imposing Catholicism on the Scottish Puritans as you claimed):
Charles I (19 November 1600 – 30 January 1649) was King of England, King of Scotland and King of Ireland from 27 March 1625 until his execution.
Charles struggled for power with the Parliament of England. He firmly believed in the Divine Right of Kings, and many in England feared that he was attempting to gain absolute power.
Religious conflicts were a notable feature of Charles' reign. He married a Catholic princess, Henrietta Maria of France, over the objections of Parliament and public opinion. Many of Charles' subjects felt that he brought the Church of England too close to Roman Catholicism. Charles' later attempts to force religious reforms upon Scotland led to the Bishops' Wars that weakened England's government and led to his downfall.
His last years were marked by the English Civil War, in which he was opposed by the forces of Parliament and by Puritans, who were hostile to his religious policies and Catholic sympathy. Charles was defeated in the first Civil War (1642 - 1645), after which Parliament expected him to accept demands for a constitutional monarchy. He instead remained defiant by attempting to forge an alliance with Scotland and escaping to the Isle of Man. This provoked a second Civil War (1648 - 1649) and a second defeat for Charles, who was tried and then executed for high treason. The monarchy was then abolished and a republic called the Commonwealth of England was declared. Charles's son, Charles II, became King after the restoration of the monarchy in 1660.
King Charles I was canonized by the Anglican Communion as Saint King Charles, the Martyr, his Feast Day is 30 January.
“‘In 1630-42, when he governed without calling a parliament, King Charles I multiplied his enemies by imposing irritating financial exactions upon various classes of the community, using prerogative powers exercised by the king in centuries past. He demanded “ship money” from the towns, fined country gentlemen (including Cromwell) for refusing to accept knighthood, raised “forced loans,” and increased customs duties. He did all this because he had no right to levy fresh taxes without the consent of Parliament; indeed, his broad aim was to secure the financial independence of the monarchy, and to fasten uniformity upon the Church. Thus the king antagonized the Puritan reformers as well as many of the country gentry and townspeople. In 1638 he became involved in a war against his Scottish subjects (he was hereditary king of Scotland as well as of England) when he tried to force upon them a prayer book similar to that in use in the English Church. They rebelled, and he was compelled to call a parliament at Westminster to ask for money to pursue the war. The accumulation of grievances against the king over eleven years made the leaders of the House of Commons aggressive and uncooperative. Cromwell at once showed himself to be a staunch Puritan, and as such gave steady support to the critics of church and government.’”
DIRECT LIFT.